tests: replace pycodestyle with black

Drop pycodestyle for code style checking in favor of black. Black is
much faster, stable PEP8 compliant code style checker offering also
automatic formatting. It aims to be very stable and produce smallest
diffs. It's used by many small and big projects.

Running checkstyle with black takes a few seconds with a terse output.
Thus, test-checkstyle-diff is no longer necessary.

Expand scope of checkstyle to all python files in the repo, replacing
test-checkstyle with checkstyle-python.

Also, fixstyle-python is now available for automatic style formatting.

Note: python virtualenv has been consolidated in test/Makefile,
test/requirements*.txt which will eventually be moved to a central
location.  This is required to simply the automated generation of
docker executor images in the CI.

Type: improvement
Change-Id: I022a326603485f58585e879ac0f697fceefbc9c8
Signed-off-by: Klement Sekera <klement.sekera@gmail.com>
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>

12 files changed, 1100 insertions, 1003 deletions

diff --git a/src/vpp-api/python/setup.py b/src/vpp-api/python/setup.py
index 8bf6def2227..18637ba21b7 100644
--- a/src/vpp-api/python/setup.py
+++ b/src/vpp-api/python/setup.py
@@ -21,15 +21,16 @@ except ImportError:
 requirements = []
 
 setup(
-    name='vpp_papi',
-    version='2.0.0',
-    description='VPP Python binding',
-    author='Ole Troan',
-    author_email='ot@cisco.com',
-    url='https://wiki.fd.io/view/VPP/Python_API',
-    license='Apache-2.0',
-    test_suite='vpp_papi.tests',
+    name="vpp_papi",
+    version="2.0.0",
+    description="VPP Python binding",
+    author="Ole Troan",
+    author_email="ot@cisco.com",
+    url="https://wiki.fd.io/view/VPP/Python_API",
+    license="Apache-2.0",
+    test_suite="vpp_papi.tests",
     install_requires=requirements,
     packages=find_packages(),
-    long_description='''VPP Python language binding.''',
-    zip_safe=True)
+    long_description="""VPP Python language binding.""",
+    zip_safe=True,
+)
diff --git a/src/vpp-api/python/vpp_papi/__init__.py b/src/vpp-api/python/vpp_papi/__init__.py
index b2b4fc78fc1..f87b6480d4e 100644
--- a/src/vpp-api/python/vpp_papi/__init__.py
+++ b/src/vpp-api/python/vpp_papi/__init__.py
@@ -3,7 +3,7 @@ from .vpp_papi import VppEnum, VppEnumType, VppEnumFlag  # noqa: F401
 from .vpp_papi import VPPIOError, VPPRuntimeError, VPPValueError  # noqa: F401
 from .vpp_papi import VPPApiClient  # noqa: F401
 from .vpp_papi import VPPApiJSONFiles  # noqa: F401
-from . macaddress import MACAddress, mac_pton, mac_ntop  # noqa: F401
+from .macaddress import MACAddress, mac_pton, mac_ntop  # noqa: F401
 
 # sorted lexicographically
 from .vpp_serializer import BaseTypes  # noqa: F401
@@ -11,6 +11,7 @@ from .vpp_serializer import VPPEnumType, VPPType, VPPTypeAlias  # noqa: F401
 from .vpp_serializer import VPPMessage, VPPUnionType  # noqa: F401
 
 import pkg_resources  # part of setuptools
+
 try:
     __version__ = pkg_resources.get_distribution("vpp_papi").version
 except (pkg_resources.DistributionNotFound):
diff --git a/src/vpp-api/python/vpp_papi/macaddress.py b/src/vpp-api/python/vpp_papi/macaddress.py
index c3b10a3c11e..8799bd7be24 100644
--- a/src/vpp-api/python/vpp_papi/macaddress.py
+++ b/src/vpp-api/python/vpp_papi/macaddress.py
@@ -18,20 +18,19 @@ import binascii
 
 
 def mac_pton(s):
-    '''Convert MAC address as text to binary'''
-    return binascii.unhexlify(s.replace(':', ''))
+    """Convert MAC address as text to binary"""
+    return binascii.unhexlify(s.replace(":", ""))
 
 
 def mac_ntop(binary):
-    '''Convert MAC address as binary to text'''
-    x = b':'.join(binascii.hexlify(binary)[i:i + 2]
-                  for i in range(0, 12, 2))
-    return str(x.decode('ascii'))
+    """Convert MAC address as binary to text"""
+    x = b":".join(binascii.hexlify(binary)[i : i + 2] for i in range(0, 12, 2))
+    return str(x.decode("ascii"))
 
 
-class MACAddress():
+class MACAddress:
     def __init__(self, mac):
-        '''MAC Address as a text-string (aa:bb:cc:dd:ee:ff) or 6 bytes'''
+        """MAC Address as a text-string (aa:bb:cc:dd:ee:ff) or 6 bytes"""
         # Of course Python 2 doesn't distinguish str from bytes
         if type(mac) is bytes and len(mac) == 6:
             self.mac_binary = mac
@@ -51,7 +50,7 @@ class MACAddress():
         return self.mac_string
 
     def __repr__(self):
-        return '%s(%s)' % (self.__class__.__name__, self.mac_string)
+        return "%s(%s)" % (self.__class__.__name__, self.mac_string)
 
     def __eq__(self, other):
 
diff --git a/src/vpp-api/python/vpp_papi/tests/test_macaddress.py b/src/vpp-api/python/vpp_papi/tests/test_macaddress.py
index 08e365afd92..e86ec75c76e 100644
--- a/src/vpp-api/python/vpp_papi/tests/test_macaddress.py
+++ b/src/vpp-api/python/vpp_papi/tests/test_macaddress.py
@@ -3,8 +3,6 @@ from vpp_papi import MACAddress
 
 
 class TestMacAddress(unittest.TestCase):
-
     def test_eq(self):
-        mac = '11:22:33:44:55:66'
-        self.assertEqual(MACAddress(mac),
-                         MACAddress(mac))
+        mac = "11:22:33:44:55:66"
+        self.assertEqual(MACAddress(mac), MACAddress(mac))
diff --git a/src/vpp-api/python/vpp_papi/tests/test_vpp_format.py b/src/vpp-api/python/vpp_papi/tests/test_vpp_format.py
index 5c179c02e0a..ae4d2c5126d 100644
--- a/src/vpp-api/python/vpp_papi/tests/test_vpp_format.py
+++ b/src/vpp-api/python/vpp_papi/tests/test_vpp_format.py
@@ -25,57 +25,64 @@ from vpp_papi import vpp_format
 
 from parameterized import parameterized
 
-ip4_addr = '1.2.3.4'
-ip4_addrn = b'\x01\x02\x03\x04'
+ip4_addr = "1.2.3.4"
+ip4_addrn = b"\x01\x02\x03\x04"
 ip4_prefix_len = 32
-ip4_prefix = '%s/%s' % (ip4_addr, ip4_prefix_len)
+ip4_prefix = "%s/%s" % (ip4_addr, ip4_prefix_len)
 ipv4_network = ipaddress.IPv4Network(text_type(ip4_prefix))
-ip4_addr_format_vl_api_address_t = {'un': {'ip4': b'\x01\x02\x03\x04'},
-                                    'af': 0}
-ip4_addr_format_vl_api_prefix_t = {'address':                                # noqa: E127,E501
-                                       {'un': {'ip4': b'\x01\x02\x03\x04'},
-                                        'af': 0},
-                                   'len': ip4_prefix_len}
-ip4_addr_format_vl_api_prefix_packed_t = {'address': b'\x01\x02\x03\x04',
-                                          'len': ip4_prefix_len}
-
-ip6_addr = 'dead::'
-ip6_addrn = b'\xde\xad\x00\x00\x00\x00\x00\x00' \
-            b'\x00\x00\x00\x00\x00\x00\x00\x00'
+ip4_addr_format_vl_api_address_t = {"un": {"ip4": b"\x01\x02\x03\x04"}, "af": 0}
+ip4_addr_format_vl_api_prefix_t = {
+    "address": {"un": {"ip4": b"\x01\x02\x03\x04"}, "af": 0},  # noqa: E127,E501
+    "len": ip4_prefix_len,
+}
+ip4_addr_format_vl_api_prefix_packed_t = {
+    "address": b"\x01\x02\x03\x04",
+    "len": ip4_prefix_len,
+}
+
+ip6_addr = "dead::"
+ip6_addrn = b"\xde\xad\x00\x00\x00\x00\x00\x00" b"\x00\x00\x00\x00\x00\x00\x00\x00"
 ip6_prefix_len = 127
-ip6_prefix = '%s/%s' % (ip6_addr, ip6_prefix_len)
+ip6_prefix = "%s/%s" % (ip6_addr, ip6_prefix_len)
 ipv6_network = ipaddress.IPv6Network(text_type(ip6_prefix))
-ip6_addr_format_vl_api_address_t = {'un': {'ip6': b'\xde\xad\x00\x00'
-                                                  b'\x00\x00\x00\x00'
-                                                  b'\x00\x00\x00\x00'
-                                                  b'\x00\x00\x00\x00'},
-                                    'af': 1}
-ip6_addr_format_vl_api_prefix_t = {'address':       # noqa: E127
-                                       {'af': 1,
-                                        'un': {
-                                            'ip6': b'\xde\xad\x00\x00'
-                                                   b'\x00\x00\x00\x00'
-                                                   b'\x00\x00\x00\x00'
-                                                   b'\x00\x00\x00\x00'}},
-                                   'len': ip6_prefix_len}
-ip6_addr_format_vl_api_prefix_packed_t = {'address': b'\xde\xad\x00\x00'   # noqa: E127,E501
-                                                     b'\x00\x00\x00\x00'
-                                                     b'\x00\x00\x00\x00'
-                                                     b'\x00\x00\x00\x00',
-                                          'len': ip6_prefix_len}
+ip6_addr_format_vl_api_address_t = {
+    "un": {
+        "ip6": b"\xde\xad\x00\x00"
+        b"\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00"
+    },
+    "af": 1,
+}
+ip6_addr_format_vl_api_prefix_t = {
+    "address": {  # noqa: E127
+        "af": 1,
+        "un": {
+            "ip6": b"\xde\xad\x00\x00"
+            b"\x00\x00\x00\x00"
+            b"\x00\x00\x00\x00"
+            b"\x00\x00\x00\x00"
+        },
+    },
+    "len": ip6_prefix_len,
+}
+ip6_addr_format_vl_api_prefix_packed_t = {
+    "address": b"\xde\xad\x00\x00"  # noqa: E127,E501
+    b"\x00\x00\x00\x00"
+    b"\x00\x00\x00\x00"
+    b"\x00\x00\x00\x00",
+    "len": ip6_prefix_len,
+}
 
 
 class TestVppFormat(unittest.TestCase):
-
     def test_format_vl_api_address_t(self):
         res = vpp_format.format_vl_api_address_t(ip4_addr)
         self.assertEqual(res, ip4_addr_format_vl_api_address_t)
 
         # PY2: raises socket.error
         # PY3: raises OSError
-        with self.assertRaises((TypeError,
-                                socket.error,
-                                OSError)):
+        with self.assertRaises((TypeError, socket.error, OSError)):
             res = vpp_format.format_vl_api_address_t(ip4_addrn)
 
         res = vpp_format.format_vl_api_address_t(ip6_addr)
@@ -84,19 +91,14 @@ class TestVppFormat(unittest.TestCase):
         with self.assertRaises(TypeError):
             es = vpp_format.format_vl_api_address_t(ip6_addrn)
 
-    @parameterized.expand([('ip4 prefix',
-                            ip4_prefix,
-                            ip4_addr_format_vl_api_prefix_t),
-                           ('ip6 prefix',
-                            ip6_prefix,
-                            ip6_addr_format_vl_api_prefix_t),
-                           ('IPv4Network',
-                            ipv4_network,
-                            ip4_addr_format_vl_api_prefix_t),
-                           ('IPv6Network',
-                            ipv6_network,
-                            ip6_addr_format_vl_api_prefix_t),
-                           ])
+    @parameterized.expand(
+        [
+            ("ip4 prefix", ip4_prefix, ip4_addr_format_vl_api_prefix_t),
+            ("ip6 prefix", ip6_prefix, ip6_addr_format_vl_api_prefix_t),
+            ("IPv4Network", ipv4_network, ip4_addr_format_vl_api_prefix_t),
+            ("IPv6Network", ipv6_network, ip6_addr_format_vl_api_prefix_t),
+        ]
+    )
     def test_format_vl_api_prefix_t(self, _, arg, expected):
         res = vpp_format.format_vl_api_prefix_t(arg)
         self.assertEqual(res, expected)
diff --git a/src/vpp-api/python/vpp_papi/tests/test_vpp_papi.py b/src/vpp-api/python/vpp_papi/tests/test_vpp_papi.py
index 99acb7c7469..2b21c83966a 100644
--- a/src/vpp-api/python/vpp_papi/tests/test_vpp_papi.py
+++ b/src/vpp-api/python/vpp_papi/tests/test_vpp_papi.py
@@ -24,7 +24,7 @@ from vpp_papi import vpp_transport_shmem
 
 class TestVppPapiVPPApiClient(unittest.TestCase):
     def test_getcontext(self):
-        vpp_papi.VPPApiClient.apidir = '.'
+        vpp_papi.VPPApiClient.apidir = "."
         c = vpp_papi.VPPApiClient(testmode=True, use_socket=True)
 
         # reset initialization at module load time.
@@ -39,7 +39,7 @@ class TestVppPapiVPPApiClientMp(unittest.TestCase):
     # run_tests.py (eg. make test TEST_JOBS=10)
 
     def test_get_context_mp(self):
-        vpp_papi.VPPApiClient.apidir = '.'
+        vpp_papi.VPPApiClient.apidir = "."
         c = vpp_papi.VPPApiClient(testmode=True, use_socket=True)
 
         # reset initialization at module load time.
@@ -243,11 +243,11 @@ class TestVppPapiLogging(unittest.TestCase):
                 pass
 
         client = Vpp
-        with self.assertLogs('vpp_papi', level='DEBUG') as cm:
+        with self.assertLogs("vpp_papi", level="DEBUG") as cm:
             vpp_papi.vpp_atexit(client)
-        self.assertEqual(cm.output, ['DEBUG:vpp_papi:Cleaning up VPP on exit'])
+        self.assertEqual(cm.output, ["DEBUG:vpp_papi:Cleaning up VPP on exit"])
 
         with self.assertRaises(AssertionError):
-            with self.assertLogs('vpp_papi.serializer', level='DEBUG') as cm:
+            with self.assertLogs("vpp_papi.serializer", level="DEBUG") as cm:
                 vpp_papi.vpp_atexit(client)
         self.assertEqual(cm.output, [])
diff --git a/src/vpp-api/python/vpp_papi/tests/test_vpp_serializer.py b/src/vpp-api/python/vpp_papi/tests/test_vpp_serializer.py
index c9b3d672d6a..eee38f00632 100755
--- a/src/vpp-api/python/vpp_papi/tests/test_vpp_serializer.py
+++ b/src/vpp-api/python/vpp_papi/tests/test_vpp_serializer.py
@@ -13,61 +13,57 @@ from ipaddress import *
 
 class TestLimits(unittest.TestCase):
     def test_string(self):
-        fixed_string = VPPType('fixed_string',
-                               [['string', 'name', 16]])
+        fixed_string = VPPType("fixed_string", [["string", "name", 16]])
 
-        b = fixed_string.pack({'name': 'foobar'})
+        b = fixed_string.pack({"name": "foobar"})
         self.assertEqual(len(b), 16)
 
         # Ensure string is nul terminated
-        self.assertEqual(b.decode('ascii')[6], '\x00')
+        self.assertEqual(b.decode("ascii")[6], "\x00")
 
         nt, size = fixed_string.unpack(b)
         self.assertEqual(size, 16)
-        self.assertEqual(nt.name, 'foobar')
+        self.assertEqual(nt.name, "foobar")
 
         # Empty string
-        b = fixed_string.pack({'name': ''})
+        b = fixed_string.pack({"name": ""})
         self.assertEqual(len(b), 16)
         nt, size = fixed_string.unpack(b)
         self.assertEqual(size, 16)
-        self.assertEqual(nt.name, '')
+        self.assertEqual(nt.name, "")
 
         # String too long
         with self.assertRaises(VPPSerializerValueError):
-            b = fixed_string.pack({'name': 'foobarfoobar1234'})
+            b = fixed_string.pack({"name": "foobarfoobar1234"})
 
-        variable_string = VPPType('variable_string',
-                                  [['string', 'name', 0]])
-        b = variable_string.pack({'name': 'foobar'})
-        self.assertEqual(len(b), 4 + len('foobar'))
+        variable_string = VPPType("variable_string", [["string", "name", 0]])
+        b = variable_string.pack({"name": "foobar"})
+        self.assertEqual(len(b), 4 + len("foobar"))
 
         nt, size = variable_string.unpack(b)
-        self.assertEqual(size, 4 + len('foobar'))
-        self.assertEqual(nt.name, 'foobar')
-        self.assertEqual(len(nt.name), len('foobar'))
+        self.assertEqual(size, 4 + len("foobar"))
+        self.assertEqual(nt.name, "foobar")
+        self.assertEqual(len(nt.name), len("foobar"))
 
     def test_limit(self):
-        limited_type = VPPType('limited_type_t',
-                               [['string', 'name', 0, {'limit': 16}]])
-        unlimited_type = VPPType('limited_type_t',
-                                 [['string', 'name', 0]])
+        limited_type = VPPType("limited_type_t", [["string", "name", 0, {"limit": 16}]])
+        unlimited_type = VPPType("limited_type_t", [["string", "name", 0]])
 
-        b = limited_type.pack({'name': 'foobar'})
+        b = limited_type.pack({"name": "foobar"})
         self.assertEqual(len(b), 10)
-        b = unlimited_type.pack({'name': 'foobar'})
+        b = unlimited_type.pack({"name": "foobar"})
         self.assertEqual(len(b), 10)
 
         with self.assertRaises(VPPSerializerValueError):
-            b = limited_type.pack({'name': 'foobar'*3})
+            b = limited_type.pack({"name": "foobar" * 3})
 
 
 class TestDefaults(unittest.TestCase):
     def test_defaults(self):
-        default_type = VPPType('default_type_t',
-                               [['u16', 'mtu', {'default': 1500, 'limit': 0}]])
-        without_default_type = VPPType('without_default_type_t',
-                                       [['u16', 'mtu']])
+        default_type = VPPType(
+            "default_type_t", [["u16", "mtu", {"default": 1500, "limit": 0}]]
+        )
+        without_default_type = VPPType("without_default_type_t", [["u16", "mtu"]])
 
         b = default_type.pack({})
         self.assertEqual(len(b), 2)
@@ -76,7 +72,7 @@ class TestDefaults(unittest.TestCase):
         self.assertEqual(nt.mtu, 1500)
 
         # distinguish between parameter 0 and parameter not passed
-        b = default_type.pack({'mtu': 0})
+        b = default_type.pack({"mtu": 0})
         self.assertEqual(len(b), 2)
         nt, size = default_type.unpack(b)
         self.assertEqual(len(b), size)
@@ -90,13 +86,15 @@ class TestDefaults(unittest.TestCase):
         self.assertEqual(nt.mtu, 0)
 
         # default enum type
-        VPPEnumType('vl_api_enum_t', [["ADDRESS_IP4", 0],
-                                      ["ADDRESS_IP6", 1],
-                                      {"enumtype": "u32"}])
+        VPPEnumType(
+            "vl_api_enum_t",
+            [["ADDRESS_IP4", 0], ["ADDRESS_IP6", 1], {"enumtype": "u32"}],
+        )
 
-        default_with_enum = VPPType('default_enum_type_t',
-                                    [['u16', 'mtu'], ['vl_api_enum_t',
-                                                      'e', {'default': 1}]])
+        default_with_enum = VPPType(
+            "default_enum_type_t",
+            [["u16", "mtu"], ["vl_api_enum_t", "e", {"default": 1}]],
+        )
 
         b = default_with_enum.pack({})
         self.assertEqual(len(b), 6)
@@ -106,275 +104,275 @@ class TestDefaults(unittest.TestCase):
 
 
 class TestAddType(unittest.TestCase):
-
     def test_union(self):
-        un = VPPUnionType('test_union',
-                          [['u8', 'is_bool'],
-                           ['u32', 'is_int']])
+        un = VPPUnionType("test_union", [["u8", "is_bool"], ["u32", "is_int"]])
 
-        b = un.pack({'is_int': 0x12345678})
+        b = un.pack({"is_int": 0x12345678})
         nt, size = un.unpack(b)
         self.assertEqual(len(b), size)
         self.assertEqual(nt.is_bool, 0x12)
         self.assertEqual(nt.is_int, 0x12345678)
 
     def test_address(self):
-        af = VPPEnumType('vl_api_address_family_t', [["ADDRESS_IP4", 0],
-                                                     ["ADDRESS_IP6", 1],
-                                                     {"enumtype": "u32"}])
-        aff = VPPEnumFlagType('vl_api_address_family_flag_t', [["ADDRESS_IP4", 0],
-                                                               ["ADDRESS_IP6", 1],
-                                                               {"enumtype": "u32"}])
-        ip4 = VPPTypeAlias('vl_api_ip4_address_t', {'type': 'u8',
-                                                    'length': 4})
-        ip6 = VPPTypeAlias('vl_api_ip6_address_t', {'type': 'u8',
-                                                    'length': 16})
-        VPPUnionType('vl_api_address_union_t',
-                     [["vl_api_ip4_address_t", "ip4"],
-                      ["vl_api_ip6_address_t", "ip6"]])
-
-        address = VPPType('vl_api_address_t',
-                          [['vl_api_address_family_t', 'af'],
-                           ['vl_api_address_union_t', 'un']])
-
-        prefix = VPPType('vl_api_prefix_t',
-                         [['vl_api_address_t', 'address'],
-                          ['u8', 'len']])
-
-        va_address_list = VPPType('list_addresses',
-                                  [['u8', 'count'],
-                                   ['vl_api_address_t', 'addresses',
-                                    0, 'count']])
-
-        message_with_va_address_list = VPPType('msg_with_vla',
-                                               [['list_addresses',
-                                                 'vla_address'],
-                                                ['u8', 'is_cool']])
-
-        b = ip4.pack(inet_pton(AF_INET, '1.1.1.1'))
+        af = VPPEnumType(
+            "vl_api_address_family_t",
+            [["ADDRESS_IP4", 0], ["ADDRESS_IP6", 1], {"enumtype": "u32"}],
+        )
+        aff = VPPEnumFlagType(
+            "vl_api_address_family_flag_t",
+            [["ADDRESS_IP4", 0], ["ADDRESS_IP6", 1], {"enumtype": "u32"}],
+        )
+        ip4 = VPPTypeAlias("vl_api_ip4_address_t", {"type": "u8", "length": 4})
+        ip6 = VPPTypeAlias("vl_api_ip6_address_t", {"type": "u8", "length": 16})
+        VPPUnionType(
+            "vl_api_address_union_t",
+            [["vl_api_ip4_address_t", "ip4"], ["vl_api_ip6_address_t", "ip6"]],
+        )
+
+        address = VPPType(
+            "vl_api_address_t",
+            [["vl_api_address_family_t", "af"], ["vl_api_address_union_t", "un"]],
+        )
+
+        prefix = VPPType(
+            "vl_api_prefix_t", [["vl_api_address_t", "address"], ["u8", "len"]]
+        )
+
+        va_address_list = VPPType(
+            "list_addresses",
+            [["u8", "count"], ["vl_api_address_t", "addresses", 0, "count"]],
+        )
+
+        message_with_va_address_list = VPPType(
+            "msg_with_vla", [["list_addresses", "vla_address"], ["u8", "is_cool"]]
+        )
+
+        b = ip4.pack(inet_pton(AF_INET, "1.1.1.1"))
         self.assertEqual(len(b), 4)
         nt, size = ip4.unpack(b)
-        self.assertEqual(str(nt), '1.1.1.1')
+        self.assertEqual(str(nt), "1.1.1.1")
 
-        b = ip6.pack(inet_pton(AF_INET6, '1::1'))
+        b = ip6.pack(inet_pton(AF_INET6, "1::1"))
         self.assertEqual(len(b), 16)
 
-        b = address.pack({'af': af.ADDRESS_IP4,
-                          'un':
-                          {'ip4': inet_pton(AF_INET, '2.2.2.2')}})
+        b = address.pack(
+            {"af": af.ADDRESS_IP4, "un": {"ip4": inet_pton(AF_INET, "2.2.2.2")}}
+        )
         self.assertEqual(len(b), 20)
 
         nt, size = address.unpack(b)
-        self.assertEqual(str(nt), '2.2.2.2')
+        self.assertEqual(str(nt), "2.2.2.2")
 
         # List of addresses
         address_list = []
         for i in range(4):
-            address_list.append({'af': af.ADDRESS_IP4,
-                                 'un':
-                                 {'ip4': inet_pton(AF_INET, '2.2.2.2')}})
-        b = va_address_list.pack({'count': len(address_list),
-                                  'addresses': address_list})
+            address_list.append(
+                {"af": af.ADDRESS_IP4, "un": {"ip4": inet_pton(AF_INET, "2.2.2.2")}}
+            )
+        b = va_address_list.pack(
+            {"count": len(address_list), "addresses": address_list}
+        )
         self.assertEqual(len(b), 81)
 
         nt, size = va_address_list.unpack(b)
-        self.assertEqual(str(nt.addresses[0]), '2.2.2.2')
-
-        b = message_with_va_address_list.pack({'vla_address':
-                                               {'count': len(address_list),
-                                                'addresses': address_list},
-                                               'is_cool': 100})
+        self.assertEqual(str(nt.addresses[0]), "2.2.2.2")
+
+        b = message_with_va_address_list.pack(
+            {
+                "vla_address": {"count": len(address_list), "addresses": address_list},
+                "is_cool": 100,
+            }
+        )
         self.assertEqual(len(b), 82)
         nt, size = message_with_va_address_list.unpack(b)
         self.assertEqual(nt.is_cool, 100)
 
     def test_address_with_prefix(self):
-        af = VPPEnumType('vl_api_address_family_t', [["ADDRESS_IP4", 0],
-                                                     ["ADDRESS_IP6", 1],
-                                                     {"enumtype": "u32"}])
-        ip4 = VPPTypeAlias('vl_api_ip4_address_t', {'type': 'u8',
-                                                    'length': 4})
-        ip6 = VPPTypeAlias('vl_api_ip6_address_t', {'type': 'u8',
-                                                    'length': 16})
-        VPPUnionType('vl_api_address_union_t',
-                     [["vl_api_ip4_address_t", "ip4"],
-                      ["vl_api_ip6_address_t", "ip6"]])
-
-        address = VPPType('vl_api_address_t',
-                          [['vl_api_address_family_t', 'af'],
-                           ['vl_api_address_union_t', 'un']])
-
-        prefix = VPPType('vl_api_prefix_t',
-                         [['vl_api_address_t', 'address'],
-                          ['u8', 'len']])
-        prefix4 = VPPType('vl_api_ip4_prefix_t',
-                          [['vl_api_ip4_address_t', 'address'],
-                          ['u8', 'len']])
-        prefix6 = VPPType('vl_api_ip6_prefix_t',
-                          [['vl_api_ip6_address_t', 'address'],
-                          ['u8', 'len']])
-
-        address_with_prefix = VPPTypeAlias('vl_api_address_with_prefix_t', {'type': 'vl_api_prefix_t' })
-        address4_with_prefix = VPPTypeAlias('vl_api_ip4_address_with_prefix_t',
-                                            {'type': 'vl_api_ip4_prefix_t' })
-        address6_with_prefix = VPPTypeAlias('vl_api_ip6_address_with_prefix_t',
-                                            {'type': 'vl_api_ip6_prefix_t' })
-
-        awp_type = VPPType('foobar_t',
-                           [['vl_api_address_with_prefix_t', 'address']])
+        af = VPPEnumType(
+            "vl_api_address_family_t",
+            [["ADDRESS_IP4", 0], ["ADDRESS_IP6", 1], {"enumtype": "u32"}],
+        )
+        ip4 = VPPTypeAlias("vl_api_ip4_address_t", {"type": "u8", "length": 4})
+        ip6 = VPPTypeAlias("vl_api_ip6_address_t", {"type": "u8", "length": 16})
+        VPPUnionType(
+            "vl_api_address_union_t",
+            [["vl_api_ip4_address_t", "ip4"], ["vl_api_ip6_address_t", "ip6"]],
+        )
+
+        address = VPPType(
+            "vl_api_address_t",
+            [["vl_api_address_family_t", "af"], ["vl_api_address_union_t", "un"]],
+        )
+
+        prefix = VPPType(
+            "vl_api_prefix_t", [["vl_api_address_t", "address"], ["u8", "len"]]
+        )
+        prefix4 = VPPType(
+            "vl_api_ip4_prefix_t", [["vl_api_ip4_address_t", "address"], ["u8", "len"]]
+        )
+        prefix6 = VPPType(
+            "vl_api_ip6_prefix_t", [["vl_api_ip6_address_t", "address"], ["u8", "len"]]
+        )
+
+        address_with_prefix = VPPTypeAlias(
+            "vl_api_address_with_prefix_t", {"type": "vl_api_prefix_t"}
+        )
+        address4_with_prefix = VPPTypeAlias(
+            "vl_api_ip4_address_with_prefix_t", {"type": "vl_api_ip4_prefix_t"}
+        )
+        address6_with_prefix = VPPTypeAlias(
+            "vl_api_ip6_address_with_prefix_t", {"type": "vl_api_ip6_prefix_t"}
+        )
+
+        awp_type = VPPType("foobar_t", [["vl_api_address_with_prefix_t", "address"]])
 
         # address with prefix
-        b = address_with_prefix.pack(IPv4Interface('2.2.2.2/24'))
+        b = address_with_prefix.pack(IPv4Interface("2.2.2.2/24"))
         self.assertEqual(len(b), 21)
         nt, size = address_with_prefix.unpack(b)
         self.assertTrue(isinstance(nt, IPv4Interface))
-        self.assertEqual(str(nt), '2.2.2.2/24')
+        self.assertEqual(str(nt), "2.2.2.2/24")
 
-        b = address_with_prefix.pack(IPv6Interface('2::2/64'))
+        b = address_with_prefix.pack(IPv6Interface("2::2/64"))
         self.assertEqual(len(b), 21)
         nt, size = address_with_prefix.unpack(b)
         self.assertTrue(isinstance(nt, IPv6Interface))
-        self.assertEqual(str(nt), '2::2/64')
+        self.assertEqual(str(nt), "2::2/64")
 
-        b = address_with_prefix.pack(IPv4Network('2.2.2.2/24', strict=False))
+        b = address_with_prefix.pack(IPv4Network("2.2.2.2/24", strict=False))
         self.assertEqual(len(b), 21)
         nt, size = address_with_prefix.unpack(b)
         self.assertTrue(isinstance(nt, IPv4Interface))
-        self.assertEqual(str(nt), '2.2.2.0/24')
+        self.assertEqual(str(nt), "2.2.2.0/24")
 
-        b = address4_with_prefix.pack('2.2.2.2/24')
+        b = address4_with_prefix.pack("2.2.2.2/24")
         self.assertEqual(len(b), 5)
         nt, size = address4_with_prefix.unpack(b)
         self.assertTrue(isinstance(nt, IPv4Interface))
-        self.assertEqual(str(nt), '2.2.2.2/24')
-        b = address4_with_prefix.pack(IPv4Interface('2.2.2.2/24'))
+        self.assertEqual(str(nt), "2.2.2.2/24")
+        b = address4_with_prefix.pack(IPv4Interface("2.2.2.2/24"))
         self.assertEqual(len(b), 5)
 
-        b = address6_with_prefix.pack('2::2/64')
+        b = address6_with_prefix.pack("2::2/64")
         self.assertEqual(len(b), 17)
         nt, size = address6_with_prefix.unpack(b)
         self.assertTrue(isinstance(nt, IPv6Interface))
-        self.assertEqual(str(nt), '2::2/64')
-        b = address6_with_prefix.pack(IPv6Interface('2::2/64'))
+        self.assertEqual(str(nt), "2::2/64")
+        b = address6_with_prefix.pack(IPv6Interface("2::2/64"))
         self.assertEqual(len(b), 17)
 
-        b = prefix.pack('192.168.10.0/24')
+        b = prefix.pack("192.168.10.0/24")
         self.assertEqual(len(b), 21)
         nt, size = prefix.unpack(b)
         self.assertTrue(isinstance(nt, IPv4Network))
-        self.assertEqual(str(nt), '192.168.10.0/24')
+        self.assertEqual(str(nt), "192.168.10.0/24")
 
-        b = awp_type.pack({'address': '1.2.3.4/24'})
+        b = awp_type.pack({"address": "1.2.3.4/24"})
         self.assertEqual(len(b), 21)
         nt, size = awp_type.unpack(b)
         self.assertTrue(isinstance(nt.address, IPv4Interface))
-        self.assertEqual(str(nt.address), '1.2.3.4/24')
+        self.assertEqual(str(nt.address), "1.2.3.4/24")
 
-        b = awp_type.pack({'address': IPv4Interface('1.2.3.4/24')})
+        b = awp_type.pack({"address": IPv4Interface("1.2.3.4/24")})
         self.assertEqual(len(b), 21)
         nt, size = awp_type.unpack(b)
         self.assertTrue(isinstance(nt.address, IPv4Interface))
-        self.assertEqual(str(nt.address), '1.2.3.4/24')
+        self.assertEqual(str(nt.address), "1.2.3.4/24")
 
     def test_recursive_address(self):
-        af = VPPEnumType('vl_api_address_family_t', [["ADDRESS_IP4", 0],
-                                                     ["ADDRESS_IP6", 1],
-                                                     {"enumtype": "u32"}])
-        ip4 = VPPTypeAlias('vl_api_ip4_address_t', {'type': 'u8',
-                                                    'length': 4})
-        b = ip4.pack('1.1.1.1')
+        af = VPPEnumType(
+            "vl_api_address_family_t",
+            [["ADDRESS_IP4", 0], ["ADDRESS_IP6", 1], {"enumtype": "u32"}],
+        )
+        ip4 = VPPTypeAlias("vl_api_ip4_address_t", {"type": "u8", "length": 4})
+        b = ip4.pack("1.1.1.1")
         self.assertEqual(len(b), 4)
         nt, size = ip4.unpack(b)
 
-        self.assertEqual(str(nt), '1.1.1.1')
+        self.assertEqual(str(nt), "1.1.1.1")
 
-        ip6 = VPPTypeAlias('vl_api_ip6_address_t', {'type': 'u8',
-                                                    'length': 16})
-        VPPUnionType('vl_api_address_union_t',
-                     [["vl_api_ip4_address_t", "ip4"],
-                      ["vl_api_ip6_address_t", "ip6"]])
+        ip6 = VPPTypeAlias("vl_api_ip6_address_t", {"type": "u8", "length": 16})
+        VPPUnionType(
+            "vl_api_address_union_t",
+            [["vl_api_ip4_address_t", "ip4"], ["vl_api_ip6_address_t", "ip6"]],
+        )
 
-        address = VPPType('vl_api_address_t',
-                          [['vl_api_address_family_t', 'af'],
-                           ['vl_api_address_union_t', 'un']])
+        address = VPPType(
+            "vl_api_address_t",
+            [["vl_api_address_family_t", "af"], ["vl_api_address_union_t", "un"]],
+        )
 
-        prefix = VPPType('vl_api_prefix_t',
-                         [['vl_api_address_t', 'address'],
-                          ['u8', 'len']])
-        message = VPPMessage('svs',
-                             [['vl_api_prefix_t', 'prefix']])
-        message_addr = VPPMessage('svs_address',
-                                  [['vl_api_address_t', 'address']])
+        prefix = VPPType(
+            "vl_api_prefix_t", [["vl_api_address_t", "address"], ["u8", "len"]]
+        )
+        message = VPPMessage("svs", [["vl_api_prefix_t", "prefix"]])
+        message_addr = VPPMessage("svs_address", [["vl_api_address_t", "address"]])
 
-        b = message_addr.pack({'address': "1::1"})
+        b = message_addr.pack({"address": "1::1"})
         self.assertEqual(len(b), 20)
         nt, size = message_addr.unpack(b)
         self.assertEqual("1::1", str(nt.address))
-        b = message_addr.pack({'address': "1.1.1.1"})
+        b = message_addr.pack({"address": "1.1.1.1"})
         self.assertEqual(len(b), 20)
         nt, size = message_addr.unpack(b)
         self.assertEqual("1.1.1.1", str(nt.address))
 
-        b = message.pack({'prefix': "1.1.1.0/24"})
+        b = message.pack({"prefix": "1.1.1.0/24"})
         self.assertEqual(len(b), 21)
         nt, size = message.unpack(b)
         self.assertEqual("1.1.1.0/24", str(nt.prefix))
 
-        message_array = VPPMessage('address_array',
-                                   [['vl_api_ip6_address_t',
-                                     'addresses', 2]])
-        b = message_array.pack({'addresses': [IPv6Address(u"1::1"), "2::2"]})
+        message_array = VPPMessage(
+            "address_array", [["vl_api_ip6_address_t", "addresses", 2]]
+        )
+        b = message_array.pack({"addresses": [IPv6Address("1::1"), "2::2"]})
         self.assertEqual(len(b), 32)
-        message_array_vla = VPPMessage('address_array_vla',
-                                       [['u32', 'num'],
-                                        ['vl_api_ip6_address_t',
-                                         'addresses', 0, 'num']])
-        b = message_array_vla.pack({'addresses': ["1::1", "2::2"], 'num': 2})
+        message_array_vla = VPPMessage(
+            "address_array_vla",
+            [["u32", "num"], ["vl_api_ip6_address_t", "addresses", 0, "num"]],
+        )
+        b = message_array_vla.pack({"addresses": ["1::1", "2::2"], "num": 2})
         self.assertEqual(len(b), 36)
 
-        message_array4 = VPPMessage('address_array4',
-                                    [['vl_api_ip4_address_t',
-                                      'addresses', 2]])
-        b = message_array4.pack({'addresses': ["1.1.1.1", "2.2.2.2"]})
+        message_array4 = VPPMessage(
+            "address_array4", [["vl_api_ip4_address_t", "addresses", 2]]
+        )
+        b = message_array4.pack({"addresses": ["1.1.1.1", "2.2.2.2"]})
         self.assertEqual(len(b), 8)
-        b = message_array4.pack({'addresses': [IPv4Address(u"1.1.1.1"),
-                                               "2.2.2.2"]})
+        b = message_array4.pack({"addresses": [IPv4Address("1.1.1.1"), "2.2.2.2"]})
         self.assertEqual(len(b), 8)
 
-        message = VPPMessage('address', [['vl_api_address_t', 'address']])
-        b = message.pack({'address': '1::1'})
+        message = VPPMessage("address", [["vl_api_address_t", "address"]])
+        b = message.pack({"address": "1::1"})
         self.assertEqual(len(b), 20)
-        b = message.pack({'address': '1.1.1.1'})
+        b = message.pack({"address": "1.1.1.1"})
         self.assertEqual(len(b), 20)
-        message = VPPMessage('prefix', [['vl_api_prefix_t', 'prefix']])
-        b = message.pack({'prefix': '1::1/130'})
+        message = VPPMessage("prefix", [["vl_api_prefix_t", "prefix"]])
+        b = message.pack({"prefix": "1::1/130"})
         self.assertEqual(len(b), 21)
-        b = message.pack({'prefix': IPv6Network(u'1::/119')})
+        b = message.pack({"prefix": IPv6Network("1::/119")})
         self.assertEqual(len(b), 21)
-        b = message.pack({'prefix': IPv4Network(u'1.1.0.0/16')})
+        b = message.pack({"prefix": IPv4Network("1.1.0.0/16")})
         self.assertEqual(len(b), 21)
 
     def test_zero_vla(self):
-        '''Default zero'ed out for VLAs'''
-        list = VPPType('vl_api_list_t',
-                       [['u8', 'count', 10]])
+        """Default zero'ed out for VLAs"""
+        list = VPPType("vl_api_list_t", [["u8", "count", 10]])
 
         # Define an embedded VLA type
-        valist = VPPType('vl_api_valist_t',
-                         [['u8', 'count'],
-                          ['u8', 'string', 0, 'count']])
+        valist = VPPType(
+            "vl_api_valist_t", [["u8", "count"], ["u8", "string", 0, "count"]]
+        )
         # Define a message
-        vamessage = VPPMessage('vamsg',
-                               [['vl_api_valist_t', 'valist'],
-                                ['u8', 'is_something']])
+        vamessage = VPPMessage(
+            "vamsg", [["vl_api_valist_t", "valist"], ["u8", "is_something"]]
+        )
 
-        message = VPPMessage('msg',
-                             [['vl_api_list_t', 'list'],
-                              ['u8', 'is_something']])
+        message = VPPMessage("msg", [["vl_api_list_t", "list"], ["u8", "is_something"]])
 
         # Pack message without VLA specified
-        b = message.pack({'is_something': 1})
-        b = vamessage.pack({'is_something': 1})
+        b = message.pack({"is_something": 1})
+        b = vamessage.pack({"is_something": 1})
 
     def test_arrays(self):
         # Test cases
@@ -382,254 +380,275 @@ class TestAddType(unittest.TestCase):
         # 2. Fixed list of variable length sub type
         # 3. Variable length type
         #
-        s = VPPType('str', [['u32', 'length'],
-                            ['u8', 'string', 0, 'length']])
+        s = VPPType("str", [["u32", "length"], ["u8", "string", 0, "length"]])
 
-        ip4 = VPPType('ip4_address', [['u8', 'address', 4]])
-        listip4 = VPPType('list_ip4_t', [['ip4_address', 'addresses', 4]])
-        valistip4 = VPPType('list_ip4_t',
-                            [['u8', 'count'],
-                             ['ip4_address', 'addresses', 0, 'count']])
+        ip4 = VPPType("ip4_address", [["u8", "address", 4]])
+        listip4 = VPPType("list_ip4_t", [["ip4_address", "addresses", 4]])
+        valistip4 = VPPType(
+            "list_ip4_t", [["u8", "count"], ["ip4_address", "addresses", 0, "count"]]
+        )
 
-        valistip4_legacy = VPPType('list_ip4_t',
-                                   [['u8', 'foo'],
-                                    ['ip4_address', 'addresses', 0]])
+        valistip4_legacy = VPPType(
+            "list_ip4_t", [["u8", "foo"], ["ip4_address", "addresses", 0]]
+        )
 
         addresses = []
         for i in range(4):
-            addresses.append({'address': inet_pton(AF_INET, '2.2.2.2')})
-        b = listip4.pack({'addresses': addresses})
+            addresses.append({"address": inet_pton(AF_INET, "2.2.2.2")})
+        b = listip4.pack({"addresses": addresses})
         self.assertEqual(len(b), 16)
         nt, size = listip4.unpack(b)
-        self.assertEqual(nt.addresses[0].address,
-                         inet_pton(AF_INET, '2.2.2.2'))
+        self.assertEqual(nt.addresses[0].address, inet_pton(AF_INET, "2.2.2.2"))
 
-        b = valistip4.pack({'count': len(addresses), 'addresses': addresses})
+        b = valistip4.pack({"count": len(addresses), "addresses": addresses})
         self.assertEqual(len(b), 17)
 
         nt, size = valistip4.unpack(b)
         self.assertEqual(nt.count, 4)
-        self.assertEqual(nt.addresses[0].address,
-                         inet_pton(AF_INET, '2.2.2.2'))
+        self.assertEqual(nt.addresses[0].address, inet_pton(AF_INET, "2.2.2.2"))
 
-        b = valistip4_legacy.pack({'foo': 1, 'addresses': addresses})
+        b = valistip4_legacy.pack({"foo": 1, "addresses": addresses})
         self.assertEqual(len(b), 17)
         nt, size = valistip4_legacy.unpack(b)
         self.assertEqual(len(nt.addresses), 4)
-        self.assertEqual(nt.addresses[0].address,
-                         inet_pton(AF_INET, '2.2.2.2'))
+        self.assertEqual(nt.addresses[0].address, inet_pton(AF_INET, "2.2.2.2"))
 
-        string = 'foobar foobar'
-        b = s.pack({'length': len(string), 'string': string.encode('utf-8')})
+        string = "foobar foobar"
+        b = s.pack({"length": len(string), "string": string.encode("utf-8")})
         nt, size = s.unpack(b)
         self.assertEqual(len(b), size)
 
     def test_string(self):
-        s = VPPType('str', [['u32', 'length'],
-                            ['u8', 'string', 0, 'length']])
+        s = VPPType("str", [["u32", "length"], ["u8", "string", 0, "length"]])
 
-        string = ''
-        b = s.pack({'length': len(string), 'string': string.encode('utf-8')})
+        string = ""
+        b = s.pack({"length": len(string), "string": string.encode("utf-8")})
         nt, size = s.unpack(b)
         self.assertEqual(len(b), size)
 
     def test_message(self):
-        foo = VPPMessage('foo', [['u16', '_vl_msg_id'],
-                                 ['u8', 'client_index'],
-                                 ['u8', 'something'],
-                                 {"crc": "0x559b9f3c"}])
-        b = foo.pack({'_vl_msg_id': 1, 'client_index': 5,
-                      'something': 200})
+        foo = VPPMessage(
+            "foo",
+            [
+                ["u16", "_vl_msg_id"],
+                ["u8", "client_index"],
+                ["u8", "something"],
+                {"crc": "0x559b9f3c"},
+            ],
+        )
+        b = foo.pack({"_vl_msg_id": 1, "client_index": 5, "something": 200})
         nt, size = foo.unpack(b)
         self.assertEqual(len(b), size)
         self.assertEqual(nt.something, 200)
 
     def test_abf(self):
 
-        fib_mpls_label = VPPType('vl_api_fib_mpls_label_t',
-                                 [['u8', 'is_uniform'],
-                                  ['u32', 'label'],
-                                  ['u8', 'ttl'],
-                                  ['u8', 'exp']])
+        fib_mpls_label = VPPType(
+            "vl_api_fib_mpls_label_t",
+            [["u8", "is_uniform"], ["u32", "label"], ["u8", "ttl"], ["u8", "exp"]],
+        )
 
-        label_stack = {'is_uniform': 0,
-                       'label': 0,
-                       'ttl': 0,
-                       'exp': 0}
+        label_stack = {"is_uniform": 0, "label": 0, "ttl": 0, "exp": 0}
 
         b = fib_mpls_label.pack(label_stack)
         self.assertEqual(len(b), 7)
 
-        fib_path = VPPType('vl_api_fib_path_t',
-                           [['u32', 'sw_if_index'],
-                            ['u32', 'table_id'],
-                            ['u8', 'weight'],
-                            ['u8', 'preference'],
-                            ['u8', 'is_local'],
-                            ['u8', 'is_drop'],
-                            ['u8', 'is_udp_encap'],
-                            ['u8', 'is_unreach'],
-                            ['u8', 'is_prohibit'],
-                            ['u8', 'is_resolve_host'],
-                            ['u8', 'is_resolve_attached'],
-                            ['u8', 'is_dvr'],
-                            ['u8', 'is_source_lookup'],
-                            ['u8', 'afi'],
-                            ['u8', 'next_hop', 16],
-                            ['u32', 'next_hop_id'],
-                            ['u32', 'rpf_id'],
-                            ['u32', 'via_label'],
-                            ['u8', 'n_labels'],
-                            ['vl_api_fib_mpls_label_t', 'label_stack', 16]])
+        fib_path = VPPType(
+            "vl_api_fib_path_t",
+            [
+                ["u32", "sw_if_index"],
+                ["u32", "table_id"],
+                ["u8", "weight"],
+                ["u8", "preference"],
+                ["u8", "is_local"],
+                ["u8", "is_drop"],
+                ["u8", "is_udp_encap"],
+                ["u8", "is_unreach"],
+                ["u8", "is_prohibit"],
+                ["u8", "is_resolve_host"],
+                ["u8", "is_resolve_attached"],
+                ["u8", "is_dvr"],
+                ["u8", "is_source_lookup"],
+                ["u8", "afi"],
+                ["u8", "next_hop", 16],
+                ["u32", "next_hop_id"],
+                ["u32", "rpf_id"],
+                ["u32", "via_label"],
+                ["u8", "n_labels"],
+                ["vl_api_fib_mpls_label_t", "label_stack", 16],
+            ],
+        )
         label_stack_list = []
         for i in range(16):
             label_stack_list.append(label_stack)
 
-        paths = {'is_udp_encap': 0,
-                 'next_hop': b'\x10\x02\x02\xac',
-                 'table_id': 0,
-                 'afi': 0,
-                 'weight': 1,
-                 'next_hop_id': 4294967295,
-                 'label_stack': label_stack_list,
-                 'n_labels': 0,
-                 'sw_if_index': 4294967295,
-                 'preference': 0}
+        paths = {
+            "is_udp_encap": 0,
+            "next_hop": b"\x10\x02\x02\xac",
+            "table_id": 0,
+            "afi": 0,
+            "weight": 1,
+            "next_hop_id": 4294967295,
+            "label_stack": label_stack_list,
+            "n_labels": 0,
+            "sw_if_index": 4294967295,
+            "preference": 0,
+        }
 
         b = fib_path.pack(paths)
-        self.assertEqual(len(b), (7*16) + 49)
+        self.assertEqual(len(b), (7 * 16) + 49)
 
-        abf_policy = VPPType('vl_api_abf_policy_t',
-                             [['u32', 'policy_id'],
-                              ['u32', 'acl_index'],
-                              ['u8', 'n_paths'],
-                              ['vl_api_fib_path_t', 'paths', 0, 'n_paths']])
+        abf_policy = VPPType(
+            "vl_api_abf_policy_t",
+            [
+                ["u32", "policy_id"],
+                ["u32", "acl_index"],
+                ["u8", "n_paths"],
+                ["vl_api_fib_path_t", "paths", 0, "n_paths"],
+            ],
+        )
 
-        policy = {
-            'n_paths': 1,
-            'paths': [paths],
-            'acl_index': 0,
-            'policy_id': 10}
+        policy = {"n_paths": 1, "paths": [paths], "acl_index": 0, "policy_id": 10}
 
         b = abf_policy.pack(policy)
-        self.assertEqual(len(b), (7*16) + 49 + 9)
-
-        abf_policy_add_del = VPPMessage('abf_policy_add_del',
-                                        [['u16', '_vl_msg_id'],
-                                         ['u32', 'client_index'],
-                                         ['u32', 'context'],
-                                         ['u8', 'is_add'],
-                                         ['vl_api_abf_policy_t', 'policy']])
-
-        b = abf_policy_add_del.pack({'is_add': 1,
-                                     'context': 66,
-                                     '_vl_msg_id': 1066,
-                                     'policy': policy})
+        self.assertEqual(len(b), (7 * 16) + 49 + 9)
+
+        abf_policy_add_del = VPPMessage(
+            "abf_policy_add_del",
+            [
+                ["u16", "_vl_msg_id"],
+                ["u32", "client_index"],
+                ["u32", "context"],
+                ["u8", "is_add"],
+                ["vl_api_abf_policy_t", "policy"],
+            ],
+        )
+
+        b = abf_policy_add_del.pack(
+            {"is_add": 1, "context": 66, "_vl_msg_id": 1066, "policy": policy}
+        )
 
         nt, size = abf_policy_add_del.unpack(b)
-        self.assertEqual(nt.policy.paths[0].next_hop,
-                         b'\x10\x02\x02\xac\x00\x00\x00\x00'
-                         b'\x00\x00\x00\x00\x00\x00\x00\x00')
+        self.assertEqual(
+            nt.policy.paths[0].next_hop,
+            b"\x10\x02\x02\xac\x00\x00\x00\x00" b"\x00\x00\x00\x00\x00\x00\x00\x00",
+        )
 
     def test_bier(self):
 
-        bier_table_id = VPPType('vl_api_bier_table_id_t',
-                                [['u8', 'bt_set'],
-                                 ['u8', 'bt_sub_domain'],
-                                 ['u8', 'bt_hdr_len_id']])
+        bier_table_id = VPPType(
+            "vl_api_bier_table_id_t",
+            [["u8", "bt_set"], ["u8", "bt_sub_domain"], ["u8", "bt_hdr_len_id"]],
+        )
 
-        bier_imp_add = VPPMessage('bier_imp_add',
-                                  [['u32', 'client_index'],
-                                   ['u32', 'context'],
-                                   ['vl_api_bier_table_id_t', 'bi_tbl_id'],
-                                   ['u16', 'bi_src'],
-                                   ['u8', 'bi_n_bytes'],
-                                   ['u8', 'bi_bytes', 0, 'bi_n_bytes']])
+        bier_imp_add = VPPMessage(
+            "bier_imp_add",
+            [
+                ["u32", "client_index"],
+                ["u32", "context"],
+                ["vl_api_bier_table_id_t", "bi_tbl_id"],
+                ["u16", "bi_src"],
+                ["u8", "bi_n_bytes"],
+                ["u8", "bi_bytes", 0, "bi_n_bytes"],
+            ],
+        )
 
-        table_id = {'bt_set': 0,
-                    'bt_sub_domain': 0,
-                    'bt_hdr_len_id': 0}
+        table_id = {"bt_set": 0, "bt_sub_domain": 0, "bt_hdr_len_id": 0}
 
-        bibytes = b'foobar'
+        bibytes = b"foobar"
 
-        b = bier_imp_add.pack({'bi_tbl_id': table_id,
-                               'bi_n_bytes': len(bibytes),
-                               'bi_bytes': bibytes})
+        b = bier_imp_add.pack(
+            {"bi_tbl_id": table_id, "bi_n_bytes": len(bibytes), "bi_bytes": bibytes}
+        )
 
         self.assertEqual(len(b), 20)
 
     def test_lisp(self):
-        VPPEnumType('vl_api_eid_type_t',
-                    [["EID_TYPE_API_PREFIX", 0],
-                     ["EID_TYPE_API_MAC", 1],
-                     ["EID_TYPE_API_NSH", 2],
-                     {"enumtype": "u32"}])
-
-        VPPTypeAlias('vl_api_mac_address_t', {'type': 'u8',
-                                              'length': 6})
-
-        VPPType('vl_api_nsh_t',
-                [["u32", "spi"],
-                 ["u8", "si"]])
-
-        VPPEnumType('vl_api_address_family_t', [["ADDRESS_IP4", 0],
-                                                ["ADDRESS_IP6", 1],
-                                                {"enumtype": "u32"}])
-        VPPTypeAlias('vl_api_ip4_address_t', {'type': 'u8',
-                                              'length': 4})
-        VPPTypeAlias('vl_api_ip6_address_t', {'type': 'u8',
-                                              'length': 16})
-        VPPUnionType('vl_api_address_union_t',
-                     [["vl_api_ip4_address_t", "ip4"],
-                      ["vl_api_ip6_address_t", "ip6"]])
-
-        VPPType('vl_api_address_t',
-                [['vl_api_address_family_t', 'af'],
-                 ['vl_api_address_union_t', 'un']])
-
-        VPPType('vl_api_prefix_t',
-                [['vl_api_address_t', 'address'],
-                 ['u8', 'len']])
-
-        VPPUnionType('vl_api_eid_address_t',
-                     [["vl_api_prefix_t", "prefix"],
-                      ["vl_api_mac_address_t", "mac"],
-                      ["vl_api_nsh_t", "nsh"]])
-
-        eid = VPPType('vl_api_eid_t',
-                      [["vl_api_eid_type_t", "type"],
-                       ["vl_api_eid_address_t", "address"]])
-
-        b = eid.pack({'type':1,
-                      'address': {
-                          'mac': MACAddress('aa:bb:cc:dd:ee:ff')}})
+        VPPEnumType(
+            "vl_api_eid_type_t",
+            [
+                ["EID_TYPE_API_PREFIX", 0],
+                ["EID_TYPE_API_MAC", 1],
+                ["EID_TYPE_API_NSH", 2],
+                {"enumtype": "u32"},
+            ],
+        )
+
+        VPPTypeAlias("vl_api_mac_address_t", {"type": "u8", "length": 6})
+
+        VPPType("vl_api_nsh_t", [["u32", "spi"], ["u8", "si"]])
+
+        VPPEnumType(
+            "vl_api_address_family_t",
+            [["ADDRESS_IP4", 0], ["ADDRESS_IP6", 1], {"enumtype": "u32"}],
+        )
+        VPPTypeAlias("vl_api_ip4_address_t", {"type": "u8", "length": 4})
+        VPPTypeAlias("vl_api_ip6_address_t", {"type": "u8", "length": 16})
+        VPPUnionType(
+            "vl_api_address_union_t",
+            [["vl_api_ip4_address_t", "ip4"], ["vl_api_ip6_address_t", "ip6"]],
+        )
+
+        VPPType(
+            "vl_api_address_t",
+            [["vl_api_address_family_t", "af"], ["vl_api_address_union_t", "un"]],
+        )
+
+        VPPType("vl_api_prefix_t", [["vl_api_address_t", "address"], ["u8", "len"]])
+
+        VPPUnionType(
+            "vl_api_eid_address_t",
+            [
+                ["vl_api_prefix_t", "prefix"],
+                ["vl_api_mac_address_t", "mac"],
+                ["vl_api_nsh_t", "nsh"],
+            ],
+        )
+
+        eid = VPPType(
+            "vl_api_eid_t",
+            [["vl_api_eid_type_t", "type"], ["vl_api_eid_address_t", "address"]],
+        )
+
+        b = eid.pack({"type": 1, "address": {"mac": MACAddress("aa:bb:cc:dd:ee:ff")}})
         self.assertEqual(len(b), 25)
         nt, size = eid.unpack(b)
-        self.assertEqual(str(nt.address.mac), 'aa:bb:cc:dd:ee:ff')
+        self.assertEqual(str(nt.address.mac), "aa:bb:cc:dd:ee:ff")
         self.assertIsNone(nt.address.prefix)
 
 
 class TestVppSerializerLogging(unittest.TestCase):
-
     def test_logger(self):
         # test logger name 'vpp_papi.serializer'
         with self.assertRaises(VPPSerializerValueError) as ctx:
-            with self.assertLogs('vpp_papi.serializer', level='DEBUG') as cm:
-                u = VPPUnionType('vl_api_eid_address_t',
-                                 [["vl_api_prefix_t", "prefix"],
-                                  ["vl_api_mac_address_t", "mac"],
-                                  ["vl_api_nsh_t", "nsh"]])
-        self.assertEqual(cm.output, ["DEBUG:vpp_papi.serializer:Unknown union type vl_api_prefix_t"])
+            with self.assertLogs("vpp_papi.serializer", level="DEBUG") as cm:
+                u = VPPUnionType(
+                    "vl_api_eid_address_t",
+                    [
+                        ["vl_api_prefix_t", "prefix"],
+                        ["vl_api_mac_address_t", "mac"],
+                        ["vl_api_nsh_t", "nsh"],
+                    ],
+                )
+        self.assertEqual(
+            cm.output, ["DEBUG:vpp_papi.serializer:Unknown union type vl_api_prefix_t"]
+        )
 
         # test parent logger name 'vpp_papi'
         with self.assertRaises(VPPSerializerValueError) as ctx:
-            with self.assertLogs('vpp_papi', level='DEBUG') as cm:
-                u = VPPUnionType('vl_api_eid_address_t',
-                                 [["vl_api_prefix_t", "prefix"],
-                                  ["vl_api_mac_address_t", "mac"],
-                                  ["vl_api_nsh_t", "nsh"]])
-        self.assertEqual(cm.output, ["DEBUG:vpp_papi.serializer:Unknown union type vl_api_prefix_t"])
-
-
-if __name__ == '__main__':
+            with self.assertLogs("vpp_papi", level="DEBUG") as cm:
+                u = VPPUnionType(
+                    "vl_api_eid_address_t",
+                    [
+                        ["vl_api_prefix_t", "prefix"],
+                        ["vl_api_mac_address_t", "mac"],
+                        ["vl_api_nsh_t", "nsh"],
+                    ],
+                )
+        self.assertEqual(
+            cm.output, ["DEBUG:vpp_papi.serializer:Unknown union type vl_api_prefix_t"]
+        )
+
+
+if __name__ == "__main__":
     unittest.main()
diff --git a/src/vpp-api/python/vpp_papi/vpp_format.py b/src/vpp-api/python/vpp_papi/vpp_format.py
index 0b85eb4fcb6..f80a781c753 100644
--- a/src/vpp-api/python/vpp_papi/vpp_format.py
+++ b/src/vpp-api/python/vpp_papi/vpp_format.py
@@ -25,8 +25,8 @@ ADDRESS_IP6 = 1
 
 
 def verify_enum_hint(e):
-    return (e.ADDRESS_IP4.value == ADDRESS_IP4) and\
-           (e.ADDRESS_IP6.value == ADDRESS_IP6)
+    return (e.ADDRESS_IP4.value == ADDRESS_IP4) and (e.ADDRESS_IP6.value == ADDRESS_IP6)
+
 
 #
 # Type conversion for input arguments and return values
@@ -35,146 +35,128 @@ def verify_enum_hint(e):
 
 def format_vl_api_address_t(args):
     try:
-        return {'un': {'ip6': inet_pton(AF_INET6, args)},
-                'af': ADDRESS_IP6}
+        return {"un": {"ip6": inet_pton(AF_INET6, args)}, "af": ADDRESS_IP6}
     # PY2: raises socket.error
     # PY3: raises OSError
     except (socket.error, OSError):
-        return {'un': {'ip4': inet_pton(AF_INET, args)},
-                'af': ADDRESS_IP4}
+        return {"un": {"ip4": inet_pton(AF_INET, args)}, "af": ADDRESS_IP4}
 
 
 def format_vl_api_prefix_t(args):
     if isinstance(args, (ipaddress.IPv4Network, ipaddress.IPv6Network)):
-        return {'address': format_vl_api_address_t(
-            str(args.network_address)),
-                'len': int(args.prefixlen)}
-    p, length = args.split('/')
-    return {'address': format_vl_api_address_t(p),
-            'len': int(length)}
+        return {
+            "address": format_vl_api_address_t(str(args.network_address)),
+            "len": int(args.prefixlen),
+        }
+    p, length = args.split("/")
+    return {"address": format_vl_api_address_t(p), "len": int(length)}
 
 
 def format_vl_api_address_with_prefix_t(args):
     if isinstance(args, (ipaddress.IPv4Interface, ipaddress.IPv6Interface)):
-        return {'address': format_vl_api_address_t(
-            str(args.network_address)),
-                'len': int(args.prefixlen)}
-    p, length = args.split('/')
-    return {'address': format_vl_api_address_t(p),
-            'len': int(length)}
+        return {
+            "address": format_vl_api_address_t(str(args.network_address)),
+            "len": int(args.prefixlen),
+        }
+    p, length = args.split("/")
+    return {"address": format_vl_api_address_t(p), "len": int(length)}
 
 
 def format_vl_api_ip6_prefix_t(args):
     if isinstance(args, ipaddress.IPv6Network):
-        return {'address': args.network_address.packed,
-                'len': int(args.prefixlen)}
-    p, length = args.split('/')
-    return {'address': inet_pton(AF_INET6, p),
-            'len': int(length)}
+        return {"address": args.network_address.packed, "len": int(args.prefixlen)}
+    p, length = args.split("/")
+    return {"address": inet_pton(AF_INET6, p), "len": int(length)}
 
 
 def format_vl_api_ip6_address_with_prefix_t(args):
     if isinstance(args, ipaddress.IPv6Interface):
-        return {'address': args.network_address.packed,
-                'len': int(args.prefixlen)}
-    p, length = args.split('/')
-    return {'address': inet_pton(AF_INET6, p),
-            'len': int(length)}
+        return {"address": args.network_address.packed, "len": int(args.prefixlen)}
+    p, length = args.split("/")
+    return {"address": inet_pton(AF_INET6, p), "len": int(length)}
 
 
 def format_vl_api_ip4_prefix_t(args):
     if isinstance(args, ipaddress.IPv4Network):
-        return {'address': args.network_address.packed,
-                'len': int(args.prefixlen)}
-    p, length = args.split('/')
-    return {'address': inet_pton(AF_INET, p),
-            'len': int(length)}
+        return {"address": args.network_address.packed, "len": int(args.prefixlen)}
+    p, length = args.split("/")
+    return {"address": inet_pton(AF_INET, p), "len": int(length)}
 
 
 def format_vl_api_ip4_address_with_prefix_t(args):
     if isinstance(args, ipaddress.IPv4Interface):
-        return {'address': args.network_address.packed,
-                'len': int(args.prefixlen)}
-    p, length = args.split('/')
-    return {'address': inet_pton(AF_INET, p),
-            'len': int(length)}
+        return {"address": args.network_address.packed, "len": int(args.prefixlen)}
+    p, length = args.split("/")
+    return {"address": inet_pton(AF_INET, p), "len": int(length)}
 
 
 conversion_table = {
-    'vl_api_ip6_address_t':
-    {
-        'IPv6Address': lambda o: o.packed,
-        'str': lambda s: inet_pton(AF_INET6, s)
+    "vl_api_ip6_address_t": {
+        "IPv6Address": lambda o: o.packed,
+        "str": lambda s: inet_pton(AF_INET6, s),
+    },
+    "vl_api_ip4_address_t": {
+        "IPv4Address": lambda o: o.packed,
+        "str": lambda s: inet_pton(AF_INET, s),
     },
-    'vl_api_ip4_address_t':
-    {
-        'IPv4Address': lambda o: o.packed,
-        'str': lambda s: inet_pton(AF_INET, s)
+    "vl_api_ip6_prefix_t": {
+        "IPv6Network": lambda o: {
+            "address": o.network_address.packed,
+            "len": o.prefixlen,
+        },
+        "str": lambda s: format_vl_api_ip6_prefix_t(s),
     },
-    'vl_api_ip6_prefix_t':
-    {
-        'IPv6Network': lambda o: {'address': o.network_address.packed,
-                                  'len': o.prefixlen},
-        'str': lambda s: format_vl_api_ip6_prefix_t(s)
+    "vl_api_ip4_prefix_t": {
+        "IPv4Network": lambda o: {
+            "address": o.network_address.packed,
+            "len": o.prefixlen,
+        },
+        "str": lambda s: format_vl_api_ip4_prefix_t(s),
     },
-    'vl_api_ip4_prefix_t':
-    {
-        'IPv4Network': lambda o: {'address': o.network_address.packed,
-                                  'len': o.prefixlen},
-        'str': lambda s: format_vl_api_ip4_prefix_t(s)
+    "vl_api_address_t": {
+        "IPv4Address": lambda o: {"af": ADDRESS_IP4, "un": {"ip4": o.packed}},
+        "IPv6Address": lambda o: {"af": ADDRESS_IP6, "un": {"ip6": o.packed}},
+        "str": lambda s: format_vl_api_address_t(s),
     },
-    'vl_api_address_t':
-    {
-        'IPv4Address': lambda o: {'af': ADDRESS_IP4, 'un': {'ip4': o.packed}},
-        'IPv6Address': lambda o: {'af': ADDRESS_IP6, 'un': {'ip6': o.packed}},
-        'str': lambda s: format_vl_api_address_t(s)
+    "vl_api_prefix_t": {
+        "IPv4Network": lambda o: {
+            "address": {"af": ADDRESS_IP4, "un": {"ip4": o.network_address.packed}},
+            "len": o.prefixlen,
+        },
+        "IPv6Network": lambda o: {
+            "address": {"af": ADDRESS_IP6, "un": {"ip6": o.network_address.packed}},
+            "len": o.prefixlen,
+        },
+        "str": lambda s: format_vl_api_prefix_t(s),
     },
-    'vl_api_prefix_t':
-    {
-        'IPv4Network': lambda o: {'address':
-                                  {'af': ADDRESS_IP4, 'un':
-                                   {'ip4': o.network_address.packed}},
-                                  'len': o.prefixlen},
-        'IPv6Network': lambda o: {'address':
-                                  {'af': ADDRESS_IP6, 'un':
-                                   {'ip6': o.network_address.packed}},
-                                  'len': o.prefixlen},
-        'str': lambda s: format_vl_api_prefix_t(s)
+    "vl_api_address_with_prefix_t": {
+        "IPv4Interface": lambda o: {
+            "address": {"af": ADDRESS_IP4, "un": {"ip4": o.packed}},
+            "len": o.network.prefixlen,
+        },
+        "IPv6Interface": lambda o: {
+            "address": {"af": ADDRESS_IP6, "un": {"ip6": o.packed}},
+            "len": o.network.prefixlen,
+        },
+        "str": lambda s: format_vl_api_address_with_prefix_t(s),
     },
-    'vl_api_address_with_prefix_t':
-    {
-        'IPv4Interface': lambda o: {'address':
-                                    {'af': ADDRESS_IP4, 'un':
-                                     {'ip4': o.packed}},
-                                    'len': o.network.prefixlen},
-        'IPv6Interface': lambda o: {'address':
-                                    {'af': ADDRESS_IP6, 'un':
-                                     {'ip6': o.packed}},
-                                    'len': o.network.prefixlen},
-        'str': lambda s: format_vl_api_address_with_prefix_t(s)
+    "vl_api_ip4_address_with_prefix_t": {
+        "IPv4Interface": lambda o: {"address": o.packed, "len": o.network.prefixlen},
+        "str": lambda s: format_vl_api_ip4_address_with_prefix_t(s),
     },
-    'vl_api_ip4_address_with_prefix_t':
-    {
-        'IPv4Interface': lambda o: {'address': o.packed,
-                                    'len': o.network.prefixlen},
-        'str': lambda s: format_vl_api_ip4_address_with_prefix_t(s)
+    "vl_api_ip6_address_with_prefix_t": {
+        "IPv6Interface": lambda o: {"address": o.packed, "len": o.network.prefixlen},
+        "str": lambda s: format_vl_api_ip6_address_with_prefix_t(s),
     },
-    'vl_api_ip6_address_with_prefix_t':
-    {
-        'IPv6Interface': lambda o: {'address': o.packed,
-                                    'len': o.network.prefixlen},
-        'str': lambda s: format_vl_api_ip6_address_with_prefix_t(s)
+    "vl_api_mac_address_t": {
+        "MACAddress": lambda o: o.packed,
+        "str": lambda s: macaddress.mac_pton(s),
     },
-    'vl_api_mac_address_t':
-    {
-        'MACAddress': lambda o: o.packed,
-        'str': lambda s: macaddress.mac_pton(s)
+    "vl_api_timestamp_t": {
+        "datetime.datetime": lambda o: (
+            o - datetime.datetime(1970, 1, 1)
+        ).total_seconds()
     },
-    'vl_api_timestamp_t':
-    {
-        'datetime.datetime': lambda o:
-        (o - datetime.datetime(1970, 1, 1)).total_seconds()
-    }
 }
 
 
@@ -197,7 +179,7 @@ def unformat_api_prefix_t(o):
         return ipaddress.IPv4Network((o.address, o.len), False)
     if isinstance(o.address, ipaddress.IPv6Address):
         return ipaddress.IPv6Network((o.address, o.len), False)
-    raise ValueError('Unknown instance {}', format(o))
+    raise ValueError("Unknown instance {}", format(o))
 
 
 def unformat_api_address_with_prefix_t(o):
@@ -217,16 +199,20 @@ def unformat_api_ip6_address_with_prefix_t(o):
 
 
 conversion_unpacker_table = {
-    'vl_api_ip6_address_t': lambda o: ipaddress.IPv6Address(o),
-    'vl_api_ip6_prefix_t': lambda o: ipaddress.IPv6Network((o.address, o.len)),
-    'vl_api_ip4_address_t': lambda o: ipaddress.IPv4Address(o),
-    'vl_api_ip4_prefix_t': lambda o: ipaddress.IPv4Network((o.address, o.len)),
-    'vl_api_address_t': lambda o: unformat_api_address_t(o),
-    'vl_api_prefix_t': lambda o: unformat_api_prefix_t(o),
-    'vl_api_address_with_prefix_t': lambda o: unformat_api_address_with_prefix_t(o),
-    'vl_api_ip4_address_with_prefix_t': lambda o: unformat_api_ip4_address_with_prefix_t(o),
-    'vl_api_ip6_address_with_prefix_t': lambda o: unformat_api_ip6_address_with_prefix_t(o),
-    'vl_api_mac_address_t': lambda o: macaddress.MACAddress(o),
-    'vl_api_timestamp_t': lambda o: datetime.datetime.fromtimestamp(o),
-    'vl_api_timedelta_t': lambda o: datetime.timedelta(seconds=o),
+    "vl_api_ip6_address_t": lambda o: ipaddress.IPv6Address(o),
+    "vl_api_ip6_prefix_t": lambda o: ipaddress.IPv6Network((o.address, o.len)),
+    "vl_api_ip4_address_t": lambda o: ipaddress.IPv4Address(o),
+    "vl_api_ip4_prefix_t": lambda o: ipaddress.IPv4Network((o.address, o.len)),
+    "vl_api_address_t": lambda o: unformat_api_address_t(o),
+    "vl_api_prefix_t": lambda o: unformat_api_prefix_t(o),
+    "vl_api_address_with_prefix_t": lambda o: unformat_api_address_with_prefix_t(o),
+    "vl_api_ip4_address_with_prefix_t": lambda o: unformat_api_ip4_address_with_prefix_t(
+        o
+    ),
+    "vl_api_ip6_address_with_prefix_t": lambda o: unformat_api_ip6_address_with_prefix_t(
+        o
+    ),
+    "vl_api_mac_address_t": lambda o: macaddress.MACAddress(o),
+    "vl_api_timestamp_t": lambda o: datetime.datetime.fromtimestamp(o),
+    "vl_api_timedelta_t": lambda o: datetime.timedelta(seconds=o),
 }
diff --git a/src/vpp-api/python/vpp_papi/vpp_papi.py b/src/vpp-api/python/vpp_papi/vpp_papi.py
index 3465f503e9e..1e5d23e59b7 100644
--- a/src/vpp-api/python/vpp_papi/vpp_papi.py
+++ b/src/vpp-api/python/vpp_papi/vpp_papi.py
@@ -30,13 +30,14 @@ import fnmatch
 import weakref
 import atexit
 import time
-from . vpp_format import verify_enum_hint
-from . vpp_serializer import VPPType, VPPEnumType, VPPEnumFlagType, VPPUnionType
-from . vpp_serializer import VPPMessage, vpp_get_type, VPPTypeAlias
+from .vpp_format import verify_enum_hint
+from .vpp_serializer import VPPType, VPPEnumType, VPPEnumFlagType, VPPUnionType
+from .vpp_serializer import VPPMessage, vpp_get_type, VPPTypeAlias
 
 try:
     import VppTransport
 except ModuleNotFoundError:
+
     class V:
         """placeholder for VppTransport as the implementation is dependent on
         VPPAPIClient's initialization values
@@ -44,15 +45,22 @@ except ModuleNotFoundError:
 
     VppTransport = V
 
-from . vpp_transport_socket import VppTransport
+from .vpp_transport_socket import VppTransport
 
-logger = logging.getLogger('vpp_papi')
+logger = logging.getLogger("vpp_papi")
 logger.addHandler(logging.NullHandler())
 
-__all__ = ('FuncWrapper', 'VppApiDynamicMethodHolder',
-           'VppEnum', 'VppEnumType', 'VppEnumFlag',
-           'VPPIOError', 'VPPRuntimeError', 'VPPValueError',
-           'VPPApiClient', )
+__all__ = (
+    "FuncWrapper",
+    "VppApiDynamicMethodHolder",
+    "VppEnum",
+    "VppEnumType",
+    "VppEnumFlag",
+    "VPPIOError",
+    "VPPRuntimeError",
+    "VPPValueError",
+    "VPPApiClient",
+)
 
 
 def metaclass(metaclass):
@@ -83,7 +91,7 @@ def vpp_atexit(vpp_weakref):
     """Clean up VPP connection on shutdown."""
     vpp_instance = vpp_weakref()
     if vpp_instance and vpp_instance.transport.connected:
-        logger.debug('Cleaning up VPP on exit')
+        logger.debug("Cleaning up VPP on exit")
         vpp_instance.disconnect()
 
 
@@ -98,9 +106,9 @@ def add_convenience_methods():
 
     def _vapi_af_name(self):
         if 6 == self._version:
-            return 'ip6'
+            return "ip6"
         if 4 == self._version:
-            return 'ip4'
+            return "ip4"
         raise ValueError("Invalid _version.")
 
     ipaddress._IPAddressBase.vapi_af = property(_vapi_af)
@@ -121,7 +129,7 @@ class FuncWrapper:
         return self._func(**kwargs)
 
     def __repr__(self):
-        return '<FuncWrapper(func=<%s(%s)>)>' % (self.__name__, self.__doc__)
+        return "<FuncWrapper(func=<%s(%s)>)>" % (self.__name__, self.__doc__)
 
 
 class VPPApiError(Exception):
@@ -161,7 +169,8 @@ class VPPApiJSONFiles:
         # perhaps we're in the 'src/scripts' or 'src/vpp-api/python' dir;
         # in which case, plot a course to likely places in the src tree
         import __main__ as main
-        if hasattr(main, '__file__'):
+
+        if hasattr(main, "__file__"):
             # get the path of the calling script
             localdir = os.path.dirname(os.path.realpath(main.__file__))
         else:
@@ -171,7 +180,7 @@ class VPPApiJSONFiles:
 
         def dmatch(dir):
             """Match dir against right-hand components of the script dir"""
-            d = dir.split('/')  # param 'dir' assumes a / separator
+            d = dir.split("/")  # param 'dir' assumes a / separator
             length = len(d)
             return len(localdir_s) > length and localdir_s[-length:] == d
 
@@ -180,43 +189,45 @@ class VPPApiJSONFiles:
             'variant'  (typically '' or '_debug')"""
             # Since 'core' and 'plugin' files are staged
             # in separate directories, we target the parent dir.
-            return os.path.sep.join((
-                srcdir,
-                'build-root',
-                'install-vpp%s-native' % variant,
-                'vpp',
-                'share',
-                'vpp',
-                'api',
-            ))
+            return os.path.sep.join(
+                (
+                    srcdir,
+                    "build-root",
+                    "install-vpp%s-native" % variant,
+                    "vpp",
+                    "share",
+                    "vpp",
+                    "api",
+                )
+            )
 
         srcdir = None
-        if dmatch('src/scripts'):
+        if dmatch("src/scripts"):
             srcdir = os.path.sep.join(localdir_s[:-2])
-        elif dmatch('src/vpp-api/python'):
+        elif dmatch("src/vpp-api/python"):
             srcdir = os.path.sep.join(localdir_s[:-3])
-        elif dmatch('test'):
+        elif dmatch("test"):
             # we're apparently running tests
             srcdir = os.path.sep.join(localdir_s[:-1])
 
         if srcdir:
             # we're in the source tree, try both the debug and release
             # variants.
-            dirs.append(sdir(srcdir, '_debug'))
-            dirs.append(sdir(srcdir, ''))
+            dirs.append(sdir(srcdir, "_debug"))
+            dirs.append(sdir(srcdir, ""))
 
         # Test for staged copies of the scripts
         # For these, since we explicitly know if we're running a debug versus
         # release variant, target only the relevant directory
-        if dmatch('build-root/install-vpp_debug-native/vpp/bin'):
+        if dmatch("build-root/install-vpp_debug-native/vpp/bin"):
             srcdir = os.path.sep.join(localdir_s[:-4])
-            dirs.append(sdir(srcdir, '_debug'))
-        if dmatch('build-root/install-vpp-native/vpp/bin'):
+            dirs.append(sdir(srcdir, "_debug"))
+        if dmatch("build-root/install-vpp-native/vpp/bin"):
             srcdir = os.path.sep.join(localdir_s[:-4])
-            dirs.append(sdir(srcdir, ''))
+            dirs.append(sdir(srcdir, ""))
 
         # finally, try the location system packages typically install into
-        dirs.append(os.path.sep.join(('', 'usr', 'share', 'vpp', 'api')))
+        dirs.append(os.path.sep.join(("", "usr", "share", "vpp", "api")))
 
         # check the directories for existence; first one wins
         for dir in dirs:
@@ -226,7 +237,7 @@ class VPPApiJSONFiles:
         return None
 
     @classmethod
-    def find_api_files(cls, api_dir=None, patterns='*'):  # -> list
+    def find_api_files(cls, api_dir=None, patterns="*"):  # -> list
         """Find API definition files from the given directory tree with the
         given pattern. If no directory is given then find_api_dir() is used
         to locate one. If no pattern is given then all definition files found
@@ -252,9 +263,9 @@ class VPPApiJSONFiles:
                 raise VPPApiError("api_dir cannot be located")
 
         if isinstance(patterns, list) or isinstance(patterns, tuple):
-            patterns = [p.strip() + '.api.json' for p in patterns]
+            patterns = [p.strip() + ".api.json" for p in patterns]
         else:
-            patterns = [p.strip() + '.api.json' for p in patterns.split(",")]
+            patterns = [p.strip() + ".api.json" for p in patterns.split(",")]
 
         api_files = []
         for root, dirnames, files in os.walk(api_dir):
@@ -281,39 +292,39 @@ class VPPApiJSONFiles:
         services = {}
         messages = {}
         try:
-            for t in api['enums']:
-                t[0] = 'vl_api_' + t[0] + '_t'
-                types[t[0]] = {'type': 'enum', 'data': t}
+            for t in api["enums"]:
+                t[0] = "vl_api_" + t[0] + "_t"
+                types[t[0]] = {"type": "enum", "data": t}
         except KeyError:
             pass
         try:
-            for t in api['enumflags']:
-                t[0] = 'vl_api_' + t[0] + '_t'
-                types[t[0]] = {'type': 'enum', 'data': t}
+            for t in api["enumflags"]:
+                t[0] = "vl_api_" + t[0] + "_t"
+                types[t[0]] = {"type": "enum", "data": t}
         except KeyError:
             pass
         try:
-            for t in api['unions']:
-                t[0] = 'vl_api_' + t[0] + '_t'
-                types[t[0]] = {'type': 'union', 'data': t}
+            for t in api["unions"]:
+                t[0] = "vl_api_" + t[0] + "_t"
+                types[t[0]] = {"type": "union", "data": t}
         except KeyError:
             pass
 
         try:
-            for t in api['types']:
-                t[0] = 'vl_api_' + t[0] + '_t'
-                types[t[0]] = {'type': 'type', 'data': t}
+            for t in api["types"]:
+                t[0] = "vl_api_" + t[0] + "_t"
+                types[t[0]] = {"type": "type", "data": t}
         except KeyError:
             pass
 
         try:
-            for t, v in api['aliases'].items():
-                types['vl_api_' + t + '_t'] = {'type': 'alias', 'data': v}
+            for t, v in api["aliases"].items():
+                types["vl_api_" + t + "_t"] = {"type": "alias", "data": v}
         except KeyError:
             pass
 
         try:
-            services.update(api['services'])
+            services.update(api["services"])
         except KeyError:
             pass
 
@@ -321,30 +332,30 @@ class VPPApiJSONFiles:
         while True:
             unresolved = {}
             for k, v in types.items():
-                t = v['data']
+                t = v["data"]
                 if not vpp_get_type(k):
-                    if v['type'] == 'enum':
+                    if v["type"] == "enum":
                         try:
                             VPPEnumType(t[0], t[1:])
                         except ValueError:
                             unresolved[k] = v
                 if not vpp_get_type(k):
-                    if v['type'] == 'enumflag':
+                    if v["type"] == "enumflag":
                         try:
                             VPPEnumFlagType(t[0], t[1:])
                         except ValueError:
                             unresolved[k] = v
-                    elif v['type'] == 'union':
+                    elif v["type"] == "union":
                         try:
                             VPPUnionType(t[0], t[1:])
                         except ValueError:
                             unresolved[k] = v
-                    elif v['type'] == 'type':
+                    elif v["type"] == "type":
                         try:
                             VPPType(t[0], t[1:])
                         except ValueError:
                             unresolved[k] = v
-                    elif v['type'] == 'alias':
+                    elif v["type"] == "alias":
                         try:
                             VPPTypeAlias(k, t)
                         except ValueError:
@@ -352,17 +363,16 @@ class VPPApiJSONFiles:
             if len(unresolved) == 0:
                 break
             if i > 3:
-                raise VPPValueError('Unresolved type definitions {}'
-                                    .format(unresolved))
+                raise VPPValueError("Unresolved type definitions {}".format(unresolved))
             types = unresolved
             i += 1
         try:
-            for m in api['messages']:
+            for m in api["messages"]:
                 try:
                     messages[m[0]] = VPPMessage(m[0], m[1:])
                 except VPPNotImplementedError:
                     ### OLE FIXME
-                    logger.error('Not implemented error for {}'.format(m[0]))
+                    logger.error("Not implemented error for {}".format(m[0]))
         except KeyError:
             pass
         return messages, services
@@ -380,6 +390,7 @@ class VPPApiClient:
     provides a means to register a callback function to receive
     these messages in a background thread.
     """
+
     apidir = None
     VPPApiError = VPPApiError
     VPPRuntimeError = VPPRuntimeError
@@ -387,11 +398,18 @@ class VPPApiClient:
     VPPNotImplementedError = VPPNotImplementedError
     VPPIOError = VPPIOError
 
-
-    def __init__(self, *, apifiles=None, testmode=False, async_thread=True,
-                 logger=None, loglevel=None,
-                 read_timeout=5, use_socket=True,
-                 server_address='/run/vpp/api.sock'):
+    def __init__(
+        self,
+        *,
+        apifiles=None,
+        testmode=False,
+        async_thread=True,
+        logger=None,
+        loglevel=None,
+        read_timeout=5,
+        use_socket=True,
+        server_address="/run/vpp/api.sock",
+    ):
         """Create a VPP API object.
 
         apifiles is a list of files containing API
@@ -406,7 +424,8 @@ class VPPApiClient:
         """
         if logger is None:
             logger = logging.getLogger(
-                "{}.{}".format(__name__, self.__class__.__name__))
+                "{}.{}".format(__name__, self.__class__.__name__)
+            )
             if loglevel is not None:
                 logger.setLevel(loglevel)
         self.logger = logger
@@ -415,8 +434,7 @@ class VPPApiClient:
         self.services = {}
         self.id_names = []
         self.id_msgdef = []
-        self.header = VPPType('header', [['u16', 'msgid'],
-                                         ['u32', 'client_index']])
+        self.header = VPPType("header", [["u16", "msgid"], ["u32", "client_index"]])
         self.apifiles = []
         self.event_callback = None
         self.message_queue = queue.Queue()
@@ -449,13 +467,13 @@ class VPPApiClient:
 
         # Basic sanity check
         if len(self.messages) == 0 and not testmode:
-            raise VPPValueError(1, 'Missing JSON message definitions')
-        if not(verify_enum_hint(VppEnum.vl_api_address_family_t)):
-            raise VPPRuntimeError("Invalid address family hints. "
-                                  "Cannot continue.")
+            raise VPPValueError(1, "Missing JSON message definitions")
+        if not (verify_enum_hint(VppEnum.vl_api_address_family_t)):
+            raise VPPRuntimeError("Invalid address family hints. " "Cannot continue.")
 
-        self.transport = VppTransport(self, read_timeout=read_timeout,
-                                      server_address=server_address)
+        self.transport = VppTransport(
+            self, read_timeout=read_timeout, server_address=server_address
+        )
         # Make sure we allow VPP to clean up the message rings.
         atexit.register(vpp_atexit, weakref.ref(self))
 
@@ -466,6 +484,7 @@ class VPPApiClient:
 
     class ContextId:
         """Multiprocessing-safe provider of unique context IDs."""
+
         def __init__(self):
             self.context = mp.Value(ctypes.c_uint, 0)
             self.lock = mp.Lock()
@@ -475,6 +494,7 @@ class VPPApiClient:
             with self.lock:
                 self.context.value += 1
                 return self.context.value
+
     get_context = ContextId()
 
     def get_type(self, name):
@@ -487,17 +507,20 @@ class VPPApiClient:
         return self._api
 
     def make_function(self, msg, i, multipart, do_async):
-        if (do_async):
+        if do_async:
+
             def f(**kwargs):
                 return self._call_vpp_async(i, msg, **kwargs)
+
         else:
+
             def f(**kwargs):
                 return self._call_vpp(i, msg, multipart, **kwargs)
 
         f.__name__ = str(msg.name)
-        f.__doc__ = ", ".join(["%s %s" %
-                               (msg.fieldtypes[j], k)
-                               for j, k in enumerate(msg.fields)])
+        f.__doc__ = ", ".join(
+            ["%s %s" % (msg.fieldtypes[j], k) for j, k in enumerate(msg.fields)]
+        )
         f.msg = msg
 
         return f
@@ -507,7 +530,7 @@ class VPPApiClient:
         self.id_msgdef = [None] * (self.vpp_dictionary_maxid + 1)
         self._api = VppApiDynamicMethodHolder()
         for name, msg in self.messages.items():
-            n = name + '_' + msg.crc[2:]
+            n = name + "_" + msg.crc[2:]
             i = self.transport.get_msg_index(n)
             if i > 0:
                 self.id_msgdef[i] = msg
@@ -518,28 +541,25 @@ class VPPApiClient:
                     f = self.make_function(msg, i, self.services[name], do_async)
                     setattr(self._api, name, FuncWrapper(f))
             else:
-                self.logger.debug(
-                    'No such message type or failed CRC checksum: %s', n)
+                self.logger.debug("No such message type or failed CRC checksum: %s", n)
 
-    def connect_internal(self, name, msg_handler, chroot_prefix, rx_qlen,
-                         do_async):
-        pfx = chroot_prefix.encode('utf-8') if chroot_prefix else None
+    def connect_internal(self, name, msg_handler, chroot_prefix, rx_qlen, do_async):
+        pfx = chroot_prefix.encode("utf-8") if chroot_prefix else None
 
-        rv = self.transport.connect(name, pfx,
-                                    msg_handler, rx_qlen)
+        rv = self.transport.connect(name, pfx, msg_handler, rx_qlen)
         if rv != 0:
-            raise VPPIOError(2, 'Connect failed')
+            raise VPPIOError(2, "Connect failed")
         self.vpp_dictionary_maxid = self.transport.msg_table_max_index()
         self._register_functions(do_async=do_async)
 
         # Initialise control ping
-        crc = self.messages['control_ping'].crc
+        crc = self.messages["control_ping"].crc
         self.control_ping_index = self.transport.get_msg_index(
-            ('control_ping' + '_' + crc[2:]))
-        self.control_ping_msgdef = self.messages['control_ping']
+            ("control_ping" + "_" + crc[2:])
+        )
+        self.control_ping_msgdef = self.messages["control_ping"]
         if self.async_thread:
-            self.event_thread = threading.Thread(
-                target=self.thread_msg_handler)
+            self.event_thread = threading.Thread(target=self.thread_msg_handler)
             self.event_thread.daemon = True
             self.event_thread.start()
         else:
@@ -556,8 +576,9 @@ class VPPApiClient:
         client and server.
         """
         msg_handler = self.transport.get_callback(do_async)
-        return self.connect_internal(name, msg_handler, chroot_prefix, rx_qlen,
-                                     do_async)
+        return self.connect_internal(
+            name, msg_handler, chroot_prefix, rx_qlen, do_async
+        )
 
     def connect_sync(self, name, chroot_prefix=None, rx_qlen=32):
         """Attach to VPP in synchronous mode. Application must poll for events.
@@ -568,8 +589,7 @@ class VPPApiClient:
         client and server.
         """
 
-        return self.connect_internal(name, None, chroot_prefix, rx_qlen,
-                                     do_async=False)
+        return self.connect_internal(name, None, chroot_prefix, rx_qlen, do_async=False)
 
     def disconnect(self):
         """Detach from VPP."""
@@ -590,42 +610,43 @@ class VPPApiClient:
         # If we have a context, then use the context to find any
         # request waiting for a reply
         context = 0
-        if hasattr(r, 'context') and r.context > 0:
+        if hasattr(r, "context") and r.context > 0:
             context = r.context
 
         if context == 0:
             # No context -> async notification that we feed to the callback
             self.message_queue.put_nowait(r)
         else:
-            raise VPPIOError(2, 'RPC reply message received in event handler')
+            raise VPPIOError(2, "RPC reply message received in event handler")
 
     def has_context(self, msg):
         if len(msg) < 10:
             return False
 
-        header = VPPType('header_with_context', [['u16', 'msgid'],
-                                                 ['u32', 'client_index'],
-                                                 ['u32', 'context']])
+        header = VPPType(
+            "header_with_context",
+            [["u16", "msgid"], ["u32", "client_index"], ["u32", "context"]],
+        )
 
         (i, ci, context), size = header.unpack(msg, 0)
-        if self.id_names[i] == 'rx_thread_exit':
+        if self.id_names[i] == "rx_thread_exit":
             return
 
         #
         # Decode message and returns a tuple.
         #
         msgobj = self.id_msgdef[i]
-        if 'context' in msgobj.field_by_name and context >= 0:
+        if "context" in msgobj.field_by_name and context >= 0:
             return True
         return False
 
     def decode_incoming_msg(self, msg, no_type_conversion=False):
         if not msg:
-            logger.warning('vpp_api.read failed')
+            logger.warning("vpp_api.read failed")
             return
 
         (i, ci), size = self.header.unpack(msg, 0)
-        if self.id_names[i] == 'rx_thread_exit':
+        if self.id_names[i] == "rx_thread_exit":
             return
 
         #
@@ -633,7 +654,7 @@ class VPPApiClient:
         #
         msgobj = self.id_msgdef[i]
         if not msgobj:
-            raise VPPIOError(2, 'Reply message undefined')
+            raise VPPIOError(2, "Reply message undefined")
 
         r, size = msgobj.unpack(msg, ntc=no_type_conversion)
         return r
@@ -654,41 +675,39 @@ class VPPApiClient:
 
     def _control_ping(self, context):
         """Send a ping command."""
-        self._call_vpp_async(self.control_ping_index,
-                             self.control_ping_msgdef,
-                             context=context)
+        self._call_vpp_async(
+            self.control_ping_index, self.control_ping_msgdef, context=context
+        )
 
     def validate_args(self, msg, kwargs):
         d = set(kwargs.keys()) - set(msg.field_by_name.keys())
         if d:
-            raise VPPValueError('Invalid argument {} to {}'
-                                .format(list(d), msg.name))
+            raise VPPValueError("Invalid argument {} to {}".format(list(d), msg.name))
 
     def _add_stat(self, name, ms):
         if not name in self.stats:
-            self.stats[name] = {'max': ms, 'count': 1, 'avg': ms}
+            self.stats[name] = {"max": ms, "count": 1, "avg": ms}
         else:
-            if ms > self.stats[name]['max']:
-                self.stats[name]['max'] = ms
-            self.stats[name]['count'] += 1
-            n = self.stats[name]['count']
-            self.stats[name]['avg'] = self.stats[name]['avg'] * (n - 1) / n + ms / n
+            if ms > self.stats[name]["max"]:
+                self.stats[name]["max"] = ms
+            self.stats[name]["count"] += 1
+            n = self.stats[name]["count"]
+            self.stats[name]["avg"] = self.stats[name]["avg"] * (n - 1) / n + ms / n
 
     def get_stats(self):
-        s = '\n=== API PAPI STATISTICS ===\n'
-        s += '{:<30} {:>4} {:>6} {:>6}\n'.format('message', 'cnt', 'avg', 'max')
-        for n in sorted(self.stats.items(), key=lambda v: v[1]['avg'], reverse=True):
-            s += '{:<30} {:>4} {:>6.2f} {:>6.2f}\n'.format(n[0], n[1]['count'],
-                                                           n[1]['avg'], n[1]['max'])
+        s = "\n=== API PAPI STATISTICS ===\n"
+        s += "{:<30} {:>4} {:>6} {:>6}\n".format("message", "cnt", "avg", "max")
+        for n in sorted(self.stats.items(), key=lambda v: v[1]["avg"], reverse=True):
+            s += "{:<30} {:>4} {:>6.2f} {:>6.2f}\n".format(
+                n[0], n[1]["count"], n[1]["avg"], n[1]["max"]
+            )
         return s
 
     def get_field_options(self, msg, fld_name):
         # when there is an option, the msgdef has 3 elements.
         # ['u32', 'ring_size', {'default': 1024}]
         for _def in self.messages[msg].msgdef:
-            if isinstance(_def, list) and \
-                    len(_def) == 3 and \
-                    _def[1] == fld_name:
+            if isinstance(_def, list) and len(_def) == 3 and _def[1] == fld_name:
                 return _def[2]
 
     def _call_vpp(self, i, msgdef, service, **kwargs):
@@ -707,25 +726,26 @@ class VPPApiClient:
         no response within the timeout window.
         """
         ts = time.time()
-        if 'context' not in kwargs:
+        if "context" not in kwargs:
             context = self.get_context()
-            kwargs['context'] = context
+            kwargs["context"] = context
         else:
-            context = kwargs['context']
-        kwargs['_vl_msg_id'] = i
+            context = kwargs["context"]
+        kwargs["_vl_msg_id"] = i
 
-        no_type_conversion = kwargs.pop('_no_type_conversion', False)
-        timeout = kwargs.pop('_timeout', None)
+        no_type_conversion = kwargs.pop("_no_type_conversion", False)
+        timeout = kwargs.pop("_timeout", None)
 
         try:
             if self.transport.socket_index:
-                kwargs['client_index'] = self.transport.socket_index
+                kwargs["client_index"] = self.transport.socket_index
         except AttributeError:
             pass
         self.validate_args(msgdef, kwargs)
 
-        s = 'Calling {}({})'.format(msgdef.name,
-            ','.join(['{!r}:{!r}'.format(k, v) for k, v in kwargs.items()]))
+        s = "Calling {}({})".format(
+            msgdef.name, ",".join(["{!r}:{!r}".format(k, v) for k, v in kwargs.items()])
+        )
         self.logger.debug(s)
 
         b = msgdef.pack(kwargs)
@@ -733,17 +753,17 @@ class VPPApiClient:
 
         self.transport.write(b)
 
-        msgreply = service['reply']
-        stream = True if 'stream' in service else False
+        msgreply = service["reply"]
+        stream = True if "stream" in service else False
         if stream:
-            if 'stream_msg' in service:
+            if "stream_msg" in service:
                 # New service['reply'] = _reply and service['stream_message'] = _details
-                stream_message = service['stream_msg']
-                modern =True
+                stream_message = service["stream_msg"]
+                modern = True
             else:
                 # Old  service['reply'] = _details
                 stream_message = msgreply
-                msgreply = 'control_ping_reply'
+                msgreply = "control_ping_reply"
                 modern = False
                 # Send a ping after the request - we use its response
                 # to detect that we have seen all results.
@@ -751,22 +771,22 @@ class VPPApiClient:
 
         # Block until we get a reply.
         rl = []
-        while (True):
+        while True:
             r = self.read_blocking(no_type_conversion, timeout)
             if r is None:
-                raise VPPIOError(2, 'VPP API client: read failed')
+                raise VPPIOError(2, "VPP API client: read failed")
             msgname = type(r).__name__
             if context not in r or r.context == 0 or context != r.context:
                 # Message being queued
                 self.message_queue.put_nowait(r)
                 continue
             if msgname != msgreply and (stream and (msgname != stream_message)):
-                print('REPLY MISMATCH', msgreply, msgname, stream_message, stream)
+                print("REPLY MISMATCH", msgreply, msgname, stream_message, stream)
             if not stream:
                 rl = r
                 break
             if msgname == msgreply:
-                if modern: # Return both reply and list
+                if modern:  # Return both reply and list
                     rl = r, rl
                 break
 
@@ -774,7 +794,7 @@ class VPPApiClient:
 
         self.transport.resume()
 
-        s = 'Return value: {!r}'.format(r)
+        s = "Return value: {!r}".format(r)
         if len(s) > 80:
             s = s[:80] + "..."
         self.logger.debug(s)
@@ -795,17 +815,17 @@ class VPPApiClient:
         The returned context will help with assigning which call
         the reply belongs to.
         """
-        if 'context' not in kwargs:
+        if "context" not in kwargs:
             context = self.get_context()
-            kwargs['context'] = context
+            kwargs["context"] = context
         else:
-            context = kwargs['context']
+            context = kwargs["context"]
         try:
             if self.transport.socket_index:
-                kwargs['client_index'] = self.transport.socket_index
+                kwargs["client_index"] = self.transport.socket_index
         except AttributeError:
-            kwargs['client_index'] = 0
-        kwargs['_vl_msg_id'] = i
+            kwargs["client_index"] = 0
+        kwargs["_vl_msg_id"] = i
         b = msg.pack(kwargs)
 
         self.transport.write(b)
@@ -891,26 +911,34 @@ class VPPApiClient:
         """Return VPPs API message table as name_crc dictionary,
         filtered by message name list."""
 
-        replies = [self.services[n]['reply'] for n in msglist]
+        replies = [self.services[n]["reply"] for n in msglist]
         message_table_filtered = {}
         for name in msglist + replies:
-            for k,v in self.transport.message_table.items():
+            for k, v in self.transport.message_table.items():
                 if k.startswith(name):
                     message_table_filtered[k] = v
                     break
         return message_table_filtered
 
     def __repr__(self):
-        return "<VPPApiClient apifiles=%s, testmode=%s, async_thread=%s, " \
-               "logger=%s, read_timeout=%s, " \
-               "server_address='%s'>" % (
-                   self._apifiles, self.testmode, self.async_thread,
-                   self.logger, self.read_timeout, self.server_address)
+        return (
+            "<VPPApiClient apifiles=%s, testmode=%s, async_thread=%s, "
+            "logger=%s, read_timeout=%s, "
+            "server_address='%s'>"
+            % (
+                self._apifiles,
+                self.testmode,
+                self.async_thread,
+                self.logger,
+                self.read_timeout,
+                self.server_address,
+            )
+        )
 
     def details_iter(self, f, **kwargs):
         cursor = 0
         while True:
-            kwargs['cursor'] = cursor
+            kwargs["cursor"] = cursor
             rv, details = f(**kwargs)
             for d in details:
                 yield d
diff --git a/src/vpp-api/python/vpp_papi/vpp_serializer.py b/src/vpp-api/python/vpp_papi/vpp_serializer.py
index 644aeac65c6..a99e16aa8f9 100644
--- a/src/vpp-api/python/vpp_papi/vpp_serializer.py
+++ b/src/vpp-api/python/vpp_papi/vpp_serializer.py
@@ -27,7 +27,7 @@ from . import vpp_format
 # logger = logging.getLogger('vpp_serializer')
 # logger.setLevel(logging.DEBUG)
 #
-logger = logging.getLogger('vpp_papi.serializer')
+logger = logging.getLogger("vpp_papi.serializer")
 
 
 def check(d):
@@ -46,8 +46,7 @@ def conversion_required(data, field_type):
 
 def conversion_packer(data, field_type):
     t = type(data).__name__
-    return types[field_type].pack(vpp_format.
-                                  conversion_table[field_type][t](data))
+    return types[field_type].pack(vpp_format.conversion_table[field_type][t](data))
 
 
 def conversion_unpacker(data, field_type):
@@ -77,30 +76,33 @@ class Packer:
                 return c._get_packer_with_options(f_type, options)
             except IndexError:
                 raise VPPSerializerValueError(
-                    "Options not supported for {}{} ({})".
-                    format(f_type, types[f_type].__class__,
-                           options))
+                    "Options not supported for {}{} ({})".format(
+                        f_type, types[f_type].__class__, options
+                    )
+                )
 
 
 class BaseTypes(Packer):
     def __init__(self, type, elements=0, options=None):
         self._type = type
         self._elements = elements
-        base_types = {'u8': '>B',
-                      'i8': '>b',
-                      'string': '>s',
-                      'u16': '>H',
-                      'i16': '>h',
-                      'u32': '>I',
-                      'i32': '>i',
-                      'u64': '>Q',
-                      'i64': '>q',
-                      'f64': '=d',
-                      'bool': '>?',
-                      'header': '>HI'}
-
-        if elements > 0 and (type == 'u8' or type == 'string'):
-            self.packer = struct.Struct('>%ss' % elements)
+        base_types = {
+            "u8": ">B",
+            "i8": ">b",
+            "string": ">s",
+            "u16": ">H",
+            "i16": ">h",
+            "u32": ">I",
+            "i32": ">i",
+            "u64": ">Q",
+            "i64": ">q",
+            "f64": "=d",
+            "bool": ">?",
+            "header": ">HI",
+        }
+
+        if elements > 0 and (type == "u8" or type == "string"):
+            self.packer = struct.Struct(">%ss" % elements)
         else:
             self.packer = struct.Struct(base_types[type])
         self.size = self.packer.size
@@ -108,8 +110,8 @@ class BaseTypes(Packer):
 
     def pack(self, data, kwargs=None):
         if data is None:  # Default to zero if not specified
-            if self.options and 'default' in self.options:
-                data = self.options['default']
+            if self.options and "default" in self.options:
+                data = self.options["default"]
             else:
                 data = 0
         return self.packer.pack(data)
@@ -122,9 +124,11 @@ class BaseTypes(Packer):
         return BaseTypes(f_type, options=options)
 
     def __repr__(self):
-        return "BaseTypes(type=%s, elements=%s, options=%s)" % (self._type,
-                                                                self._elements,
-                                                                self.options)
+        return "BaseTypes(type=%s, elements=%s, options=%s)" % (
+            self._type,
+            self._elements,
+            self.options,
+        )
 
 
 class String(Packer):
@@ -132,13 +136,15 @@ class String(Packer):
         self.name = name
         self.num = num
         self.size = 1
-        self.length_field_packer = BaseTypes('u32')
-        self.limit = options['limit'] if 'limit' in options else num
+        self.length_field_packer = BaseTypes("u32")
+        self.limit = options["limit"] if "limit" in options else num
         self.fixed = True if num else False
         if self.fixed and not self.limit:
             raise VPPSerializerValueError(
-                "Invalid combination for: {}, {} fixed:{} limit:{}".
-                format(name, options, self.fixed, self.limit))
+                "Invalid combination for: {}, {} fixed:{} limit:{}".format(
+                    name, options, self.fixed, self.limit
+                )
+            )
 
     def pack(self, list, kwargs=None):
         if not list:
@@ -147,34 +153,42 @@ class String(Packer):
             return self.length_field_packer.pack(0) + b""
         if self.limit and len(list) > self.limit - 1:
             raise VPPSerializerValueError(
-                "Invalid argument length for: {}, {} maximum {}".
-                format(list, len(list), self.limit - 1))
+                "Invalid argument length for: {}, {} maximum {}".format(
+                    list, len(list), self.limit - 1
+                )
+            )
         if self.fixed:
-            return list.encode('ascii').ljust(self.limit, b'\x00')
-        return self.length_field_packer.pack(len(list)) + list.encode('ascii')
+            return list.encode("ascii").ljust(self.limit, b"\x00")
+        return self.length_field_packer.pack(len(list)) + list.encode("ascii")
 
     def unpack(self, data, offset=0, result=None, ntc=False):
         if self.fixed:
-            p = BaseTypes('u8', self.num)
+            p = BaseTypes("u8", self.num)
             s = p.unpack(data, offset)
-            s2 = s[0].split(b'\0', 1)[0]
-            return (s2.decode('ascii'), self.num)
+            s2 = s[0].split(b"\0", 1)[0]
+            return (s2.decode("ascii"), self.num)
 
-        length, length_field_size = self.length_field_packer.unpack(data,
-                                                                    offset)
+        length, length_field_size = self.length_field_packer.unpack(data, offset)
         if length == 0:
-            return '', 0
-        p = BaseTypes('u8', length)
+            return "", 0
+        p = BaseTypes("u8", length)
         x, size = p.unpack(data, offset + length_field_size)
-        return (x.decode('ascii', errors='replace'), size + length_field_size)
-
-
-types = {'u8': BaseTypes('u8'), 'i8': BaseTypes('i8'),
-         'u16': BaseTypes('u16'), 'i16': BaseTypes('i16'),
-         'u32': BaseTypes('u32'), 'i32': BaseTypes('i32'),
-         'u64': BaseTypes('u64'), 'i64': BaseTypes('i64'),
-         'f64': BaseTypes('f64'),
-         'bool': BaseTypes('bool'), 'string': String}
+        return (x.decode("ascii", errors="replace"), size + length_field_size)
+
+
+types = {
+    "u8": BaseTypes("u8"),
+    "i8": BaseTypes("i8"),
+    "u16": BaseTypes("u16"),
+    "i16": BaseTypes("i16"),
+    "u32": BaseTypes("u32"),
+    "i32": BaseTypes("i32"),
+    "u64": BaseTypes("u64"),
+    "i64": BaseTypes("i64"),
+    "f64": BaseTypes("f64"),
+    "bool": BaseTypes("bool"),
+    "string": String,
+}
 
 class_types = {}
 
@@ -202,32 +216,34 @@ class FixedList_u8(Packer):
         """Packs a fixed length bytestring. Left-pads with zeros
         if input data is too short."""
         if not data:
-            return b'\x00' * self.size
+            return b"\x00" * self.size
 
         if len(data) > self.num:
             raise VPPSerializerValueError(
                 'Fixed list length error for "{}", got: {}'
-                ' expected: {}'
-                .format(self.name, len(data), self.num))
+                " expected: {}".format(self.name, len(data), self.num)
+            )
 
         try:
             return self.packer.pack(data)
         except struct.error:
             raise VPPSerializerValueError(
-                'Packing failed for "{}" {}'
-                .format(self.name, kwargs))
+                'Packing failed for "{}" {}'.format(self.name, kwargs)
+            )
 
     def unpack(self, data, offset=0, result=None, ntc=False):
         if len(data[offset:]) < self.num:
             raise VPPSerializerValueError(
                 'Invalid array length for "{}" got {}'
-                ' expected {}'
-                .format(self.name, len(data[offset:]), self.num))
+                " expected {}".format(self.name, len(data[offset:]), self.num)
+            )
         return self.packer.unpack(data, offset)
 
     def __repr__(self):
         return "FixedList_u8(name=%s, field_type=%s, num=%s)" % (
-            self.name, self.field_type, self.num
+            self.name,
+            self.field_type,
+            self.num,
         )
 
 
@@ -242,8 +258,10 @@ class FixedList(Packer):
     def pack(self, list, kwargs):
         if len(list) != self.num:
             raise VPPSerializerValueError(
-                'Fixed list length error, got: {} expected: {}'
-                .format(len(list), self.num))
+                "Fixed list length error, got: {} expected: {}".format(
+                    len(list), self.num
+                )
+            )
         b = bytes()
         for e in list:
             b += self.packer.pack(e)
@@ -262,7 +280,10 @@ class FixedList(Packer):
 
     def __repr__(self):
         return "FixedList(name=%s, field_type=%s, num=%s)" % (
-            self.name, self.field_type, self.num)
+            self.name,
+            self.field_type,
+            self.num,
+        )
 
 
 class VLAList(Packer):
@@ -279,13 +300,15 @@ class VLAList(Packer):
             return b""
         if len(lst) != kwargs[self.length_field]:
             raise VPPSerializerValueError(
-                'Variable length error, got: {} expected: {}'
-                .format(len(lst), kwargs[self.length_field]))
+                "Variable length error, got: {} expected: {}".format(
+                    len(lst), kwargs[self.length_field]
+                )
+            )
 
         # u8 array
         if self.packer.size == 1:
             if isinstance(lst, list):
-                return b''.join(lst)
+                return b"".join(lst)
             return bytes(lst)
 
         b = bytes()
@@ -300,8 +323,8 @@ class VLAList(Packer):
         # u8 array
         if self.packer.size == 1:
             if result[self.index] == 0:
-                return b'', 0
-            p = BaseTypes('u8', result[self.index])
+                return b"", 0
+            p = BaseTypes("u8", result[self.index])
             return p.unpack(data, offset, ntc=ntc)
 
         r = []
@@ -313,10 +336,12 @@ class VLAList(Packer):
         return r, total
 
     def __repr__(self):
-        return "VLAList(name=%s, field_type=%s, " \
-               "len_field_name=%s, index=%s)" % (
-                   self.name, self.field_type, self.length_field, self.index
-               )
+        return "VLAList(name=%s, field_type=%s, " "len_field_name=%s, index=%s)" % (
+            self.name,
+            self.field_type,
+            self.length_field,
+            self.index,
+        )
 
 
 class VLAList_legacy(Packer):
@@ -340,7 +365,8 @@ class VLAList_legacy(Packer):
         # Return a list of arguments
         if (len(data) - offset) % self.packer.size:
             raise VPPSerializerValueError(
-                'Legacy Variable Length Array length mismatch.')
+                "Legacy Variable Length Array length mismatch."
+            )
         elements = int((len(data) - offset) / self.packer.size)
         r = []
         for e in range(elements):
@@ -351,9 +377,7 @@ class VLAList_legacy(Packer):
         return r, total
 
     def __repr__(self):
-        return "VLAList_legacy(name=%s, field_type=%s)" % (
-            self.name, self.field_type
-        )
+        return "VLAList_legacy(name=%s, field_type=%s)" % (self.name, self.field_type)
 
 
 # Will change to IntEnum after 21.04 release
@@ -361,16 +385,16 @@ class VPPEnumType(Packer):
     output_class = IntFlag
 
     def __init__(self, name, msgdef, options=None):
-        self.size = types['u32'].size
+        self.size = types["u32"].size
         self.name = name
-        self.enumtype = 'u32'
+        self.enumtype = "u32"
         self.msgdef = msgdef
         e_hash = {}
         for f in msgdef:
-            if type(f) is dict and 'enumtype' in f:
-                if f['enumtype'] != 'u32':
-                    self.size = types[f['enumtype']].size
-                    self.enumtype = f['enumtype']
+            if type(f) is dict and "enumtype" in f:
+                if f["enumtype"] != "u32":
+                    self.size = types[f["enumtype"]].size
+                    self.enumtype = f["enumtype"]
                 continue
             ename, evalue = f
             e_hash[ename] = evalue
@@ -387,8 +411,8 @@ class VPPEnumType(Packer):
 
     def pack(self, data, kwargs=None):
         if data is None:  # Default to zero if not specified
-            if self.options and 'default' in self.options:
-                data = self.options['default']
+            if self.options and "default" in self.options:
+                data = self.options["default"]
             else:
                 data = 0
 
@@ -404,7 +428,10 @@ class VPPEnumType(Packer):
 
     def __repr__(self):
         return "%s(name=%s, msgdef=%s, options=%s)" % (
-            self.__class__.__name__, self.name, self.msgdef, self.options
+            self.__class__.__name__,
+            self.name,
+            self.msgdef,
+            self.options,
         )
 
 
@@ -424,14 +451,13 @@ class VPPUnionType(Packer):
         fields = []
         self.packers = collections.OrderedDict()
         for i, f in enumerate(msgdef):
-            if type(f) is dict and 'crc' in f:
-                self.crc = f['crc']
+            if type(f) is dict and "crc" in f:
+                self.crc = f["crc"]
                 continue
             f_type, f_name = f
             if f_type not in types:
-                logger.debug('Unknown union type {}'.format(f_type))
-                raise VPPSerializerValueError(
-                    'Unknown message type {}'.format(f_type))
+                logger.debug("Unknown union type {}".format(f_type))
+                raise VPPSerializerValueError("Unknown message type {}".format(f_type))
             fields.append(f_name)
             size = types[f_type].size
             self.packers[f_name] = types[f_type]
@@ -445,14 +471,14 @@ class VPPUnionType(Packer):
     # Union of variable length?
     def pack(self, data, kwargs=None):
         if not data:
-            return b'\x00' * self.size
+            return b"\x00" * self.size
 
         for k, v in data.items():
             logger.debug("Key: {} Value: {}".format(k, v))
             b = self.packers[k].pack(v, kwargs)
             break
         r = bytearray(self.size)
-        r[:len(b)] = b
+        r[: len(b)] = b
         return r
 
     def unpack(self, data, offset=0, result=None, ntc=False):
@@ -466,25 +492,24 @@ class VPPUnionType(Packer):
         return self.tuple._make(r), maxsize
 
     def __repr__(self):
-        return"VPPUnionType(name=%s, msgdef=%r)" % (self.name, self.msgdef)
+        return "VPPUnionType(name=%s, msgdef=%r)" % (self.name, self.msgdef)
 
 
 class VPPTypeAlias(Packer):
     def __init__(self, name, msgdef, options=None):
         self.name = name
         self.msgdef = msgdef
-        t = vpp_get_type(msgdef['type'])
+        t = vpp_get_type(msgdef["type"])
         if not t:
-            raise ValueError('No such type: {}'.format(msgdef['type']))
-        if 'length' in msgdef:
-            if msgdef['length'] == 0:
+            raise ValueError("No such type: {}".format(msgdef["type"]))
+        if "length" in msgdef:
+            if msgdef["length"] == 0:
                 raise ValueError()
-            if msgdef['type'] == 'u8':
-                self.packer = FixedList_u8(name, msgdef['type'],
-                                           msgdef['length'])
+            if msgdef["type"] == "u8":
+                self.packer = FixedList_u8(name, msgdef["type"], msgdef["length"])
                 self.size = self.packer.size
             else:
-                self.packer = FixedList(name, msgdef['type'], msgdef['length'])
+                self.packer = FixedList(name, msgdef["type"], msgdef["length"])
         else:
             self.packer = t
             self.size = t.size
@@ -498,11 +523,11 @@ class VPPTypeAlias(Packer):
             try:
                 return conversion_packer(data, self.name)
             # Python 2 and 3 raises different exceptions from inet_pton
-            except(OSError, socket.error, TypeError):
+            except (OSError, socket.error, TypeError):
                 pass
         if data is None:  # Default to zero if not specified
-            if self.options and 'default' in self.options:
-                data = self.options['default']
+            if self.options and "default" in self.options:
+                data = self.options["default"]
             else:
                 data = 0
 
@@ -525,7 +550,10 @@ class VPPTypeAlias(Packer):
 
     def __repr__(self):
         return "VPPTypeAlias(name=%s, msgdef=%s, options=%s)" % (
-            self.name, self.msgdef, self.options)
+            self.name,
+            self.msgdef,
+            self.options,
+        )
 
 
 class VPPType(Packer):
@@ -539,17 +567,16 @@ class VPPType(Packer):
         self.field_by_name = {}
         size = 0
         for i, f in enumerate(msgdef):
-            if type(f) is dict and 'crc' in f:
-                self.crc = f['crc']
+            if type(f) is dict and "crc" in f:
+                self.crc = f["crc"]
                 continue
             f_type, f_name = f[:2]
             self.fields.append(f_name)
             self.field_by_name[f_name] = None
             self.fieldtypes.append(f_type)
             if f_type not in types:
-                logger.debug('Unknown type {}'.format(f_type))
-                raise VPPSerializerValueError(
-                    'Unknown message type {}'.format(f_type))
+                logger.debug("Unknown type {}".format(f_type))
+                raise VPPSerializerValueError("Unknown message type {}".format(f_type))
 
             fieldlen = len(f)
             options = [x for x in f if type(x) is dict]
@@ -561,16 +588,16 @@ class VPPType(Packer):
             if fieldlen == 3:  # list
                 list_elements = f[2]
                 if list_elements == 0:
-                    if f_type == 'string':
+                    if f_type == "string":
                         p = String(f_name, 0, self.options)
                     else:
                         p = VLAList_legacy(f_name, f_type)
                     self.packers.append(p)
-                elif f_type == 'u8':
+                elif f_type == "u8":
                     p = FixedList_u8(f_name, f_type, list_elements)
                     self.packers.append(p)
                     size += p.size
-                elif f_type == 'string':
+                elif f_type == "string":
                     p = String(f_name, list_elements, self.options)
                     self.packers.append(p)
                     size += p.size
@@ -584,7 +611,7 @@ class VPPType(Packer):
                 self.packers.append(p)
             else:
                 # default support for types that decay to basetype
-                if 'default' in self.options:
+                if "default" in self.options:
                     p = self.get_packer_with_options(f_type, self.options)
                 else:
                     p = types[f_type]
@@ -609,8 +636,8 @@ class VPPType(Packer):
         for i, a in enumerate(self.fields):
             if data and type(data) is not dict and a not in data:
                 raise VPPSerializerValueError(
-                    "Invalid argument: {} expected {}.{}".
-                    format(data, self.name, a))
+                    "Invalid argument: {} expected {}.{}".format(data, self.name, a)
+                )
 
             # Defaulting to zero.
             if not data or a not in data:  # Default to 0
@@ -651,7 +678,9 @@ class VPPType(Packer):
 
     def __repr__(self):
         return "%s(name=%s, msgdef=%s)" % (
-            self.__class__.__name__, self.name, self.msgdef
+            self.__class__.__name__,
+            self.name,
+            self.msgdef,
         )
 
 
diff --git a/src/vpp-api/python/vpp_papi/vpp_stats.py b/src/vpp-api/python/vpp_papi/vpp_stats.py
index 0b1c701a430..4a342b68a8f 100755
--- a/src/vpp-api/python/vpp_papi/vpp_stats.py
+++ b/src/vpp-api/python/vpp_papi/vpp_stats.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 #
 
-'''
+"""
 This module implement Python access to the VPP statistics segment. It
 accesses the data structures directly in shared memory.
 VPP uses optimistic locking, so data structures may change underneath
@@ -39,7 +39,7 @@ stat['/if/rx'][:, 1].sum_packets() - returns the sum of packet counters for
                                      interface 1 on all threads
 stat['/if/rx-miss'][:, 1].sum() - returns the sum of packet counters for
                                   interface 1 on all threads for simple counters
-'''
+"""
 
 import os
 import socket
@@ -50,31 +50,36 @@ import time
 import unittest
 import re
 
+
 def recv_fd(sock):
-    '''Get file descriptor for memory map'''
-    fds = array.array("i")   # Array of ints
+    """Get file descriptor for memory map"""
+    fds = array.array("i")  # Array of ints
     _, ancdata, _, _ = sock.recvmsg(0, socket.CMSG_LEN(4))
     for cmsg_level, cmsg_type, cmsg_data in ancdata:
         if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
-            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
+            fds.frombytes(cmsg_data[: len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
     return list(fds)[0]
 
-VEC_LEN_FMT = Struct('I')
+
+VEC_LEN_FMT = Struct("I")
+
+
 def get_vec_len(stats, vector_offset):
-    '''Equivalent to VPP vec_len()'''
+    """Equivalent to VPP vec_len()"""
     return VEC_LEN_FMT.unpack_from(stats.statseg, vector_offset - 8)[0]
 
+
 def get_string(stats, ptr):
-    '''Get a string from a VPP vector'''
+    """Get a string from a VPP vector"""
     namevector = ptr - stats.base
     namevectorlen = get_vec_len(stats, namevector)
     if namevector + namevectorlen >= stats.size:
-        raise IOError('String overruns stats segment')
-    return stats.statseg[namevector:namevector+namevectorlen-1].decode('ascii')
+        raise IOError("String overruns stats segment")
+    return stats.statseg[namevector : namevector + namevectorlen - 1].decode("ascii")
 
 
 class StatsVector:
-    '''A class representing a VPP vector'''
+    """A class representing a VPP vector"""
 
     def __init__(self, stats, ptr, fmt):
         self.vec_start = ptr - stats.base
@@ -86,28 +91,35 @@ class StatsVector:
         self.stats = stats
 
         if self.vec_start + self.vec_len * self.elementsize >= stats.size:
-            raise IOError('Vector overruns stats segment')
+            raise IOError("Vector overruns stats segment")
 
     def __iter__(self):
         with self.stats.lock:
-            return self.struct.iter_unpack(self.statseg[self.vec_start:self.vec_start +
-                                                        self.elementsize*self.vec_len])
+            return self.struct.iter_unpack(
+                self.statseg[
+                    self.vec_start : self.vec_start + self.elementsize * self.vec_len
+                ]
+            )
 
     def __getitem__(self, index):
         if index > self.vec_len:
-            raise IOError('Index beyond end of vector')
+            raise IOError("Index beyond end of vector")
         with self.stats.lock:
             if self.fmtlen == 1:
-                return self.struct.unpack_from(self.statseg, self.vec_start +
-                                               (index * self.elementsize))[0]
-            return self.struct.unpack_from(self.statseg, self.vec_start +
-                                           (index * self.elementsize))
+                return self.struct.unpack_from(
+                    self.statseg, self.vec_start + (index * self.elementsize)
+                )[0]
+            return self.struct.unpack_from(
+                self.statseg, self.vec_start + (index * self.elementsize)
+            )
+
+
+class VPPStats:
+    """Main class implementing Python access to the VPP statistics segment"""
 
-class VPPStats():
-    '''Main class implementing Python access to the VPP statistics segment'''
     # pylint: disable=too-many-instance-attributes
-    shared_headerfmt = Struct('QPQQPP')
-    default_socketname = '/run/vpp/stats.sock'
+    shared_headerfmt = Struct("QPQQPP")
+    default_socketname = "/run/vpp/stats.sock"
 
     def __init__(self, socketname=default_socketname, timeout=10):
         self.socketname = socketname
@@ -120,7 +132,7 @@ class VPPStats():
         self.statseg = 0
 
     def connect(self):
-        '''Connect to stats segment'''
+        """Connect to stats segment"""
         if self.connected:
             return
         sock = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
@@ -130,61 +142,64 @@ class VPPStats():
         sock.close()
 
         stat_result = os.fstat(mfd)
-        self.statseg = mmap.mmap(mfd, stat_result.st_size, mmap.PROT_READ, mmap.MAP_SHARED)
+        self.statseg = mmap.mmap(
+            mfd, stat_result.st_size, mmap.PROT_READ, mmap.MAP_SHARED
+        )
         os.close(mfd)
 
         self.size = stat_result.st_size
         if self.version != 2:
-            raise Exception('Incompatbile stat segment version {}'
-                            .format(self.version))
+            raise Exception("Incompatbile stat segment version {}".format(self.version))
 
         self.refresh()
         self.connected = True
 
     def disconnect(self):
-        '''Disconnect from stats segment'''
+        """Disconnect from stats segment"""
         if self.connected:
             self.statseg.close()
             self.connected = False
 
     @property
     def version(self):
-        '''Get version of stats segment'''
+        """Get version of stats segment"""
         return self.shared_headerfmt.unpack_from(self.statseg)[0]
 
     @property
     def base(self):
-        '''Get base pointer of stats segment'''
+        """Get base pointer of stats segment"""
         return self.shared_headerfmt.unpack_from(self.statseg)[1]
 
     @property
     def epoch(self):
-        '''Get current epoch value from stats segment'''
+        """Get current epoch value from stats segment"""
         return self.shared_headerfmt.unpack_from(self.statseg)[2]
 
     @property
     def in_progress(self):
-        '''Get value of in_progress from stats segment'''
+        """Get value of in_progress from stats segment"""
         return self.shared_headerfmt.unpack_from(self.statseg)[3]
 
     @property
     def directory_vector(self):
-        '''Get pointer of directory vector'''
+        """Get pointer of directory vector"""
         return self.shared_headerfmt.unpack_from(self.statseg)[4]
 
-    elementfmt = 'IQ128s'
+    elementfmt = "IQ128s"
 
     def refresh(self, blocking=True):
-        '''Refresh directory vector cache (epoch changed)'''
+        """Refresh directory vector cache (epoch changed)"""
         directory = {}
         directory_by_idx = {}
         while True:
             try:
                 with self.lock:
                     self.last_epoch = self.epoch
-                    for i, direntry in enumerate(StatsVector(self, self.directory_vector, self.elementfmt)):
-                        path_raw = direntry[2].find(b'\x00')
-                        path = direntry[2][:path_raw].decode('ascii')
+                    for i, direntry in enumerate(
+                        StatsVector(self, self.directory_vector, self.elementfmt)
+                    ):
+                        path_raw = direntry[2].find(b"\x00")
+                        path = direntry[2][:path_raw].decode("ascii")
                         directory[path] = StatsEntry(direntry[0], direntry[1])
                         directory_by_idx[i] = path
                     self.directory = directory
@@ -210,14 +225,12 @@ class VPPStats():
     def __iter__(self):
         return iter(self.directory.items())
 
-
     def set_errors(self, blocking=True):
-        '''Return dictionary of error counters > 0'''
+        """Return dictionary of error counters > 0"""
         if not self.connected:
             self.connect()
 
-        errors = {k: v for k, v in self.directory.items()
-                  if k.startswith("/err/")}
+        errors = {k: v for k, v in self.directory.items() if k.startswith("/err/")}
         result = {}
         for k in errors:
             try:
@@ -229,23 +242,23 @@ class VPPStats():
         return result
 
     def set_errors_str(self, blocking=True):
-        '''Return all errors counters > 0 pretty printed'''
-        error_string = ['ERRORS:']
+        """Return all errors counters > 0 pretty printed"""
+        error_string = ["ERRORS:"]
         error_counters = self.set_errors(blocking)
         for k in sorted(error_counters):
-            error_string.append('{:<60}{:>10}'.format(k, error_counters[k]))
-        return '%s\n' % '\n'.join(error_string)
+            error_string.append("{:<60}{:>10}".format(k, error_counters[k]))
+        return "%s\n" % "\n".join(error_string)
 
     def get_counter(self, name, blocking=True):
-        '''Alternative call to __getitem__'''
+        """Alternative call to __getitem__"""
         return self.__getitem__(name, blocking)
 
     def get_err_counter(self, name, blocking=True):
-        '''Alternative call to __getitem__'''
+        """Alternative call to __getitem__"""
         return self.__getitem__(name, blocking).sum()
 
     def ls(self, patterns):
-        '''Returns list of counters matching pattern'''
+        """Returns list of counters matching pattern"""
         # pylint: disable=invalid-name
         if not self.connected:
             self.connect()
@@ -255,20 +268,24 @@ class VPPStats():
         if self.last_epoch != self.epoch:
             self.refresh()
 
-        return [k for k, v in self.directory.items()
-                if any(re.match(pattern, k) for pattern in regex)]
+        return [
+            k
+            for k, v in self.directory.items()
+            if any(re.match(pattern, k) for pattern in regex)
+        ]
 
     def dump(self, counters, blocking=True):
-        '''Given a list of counters return a dictionary of results'''
+        """Given a list of counters return a dictionary of results"""
         if not self.connected:
             self.connect()
         result = {}
         for cnt in counters:
-            result[cnt] = self.__getitem__(cnt,blocking)
+            result[cnt] = self.__getitem__(cnt, blocking)
         return result
 
-class StatsLock():
-    '''Stat segment optimistic locking'''
+
+class StatsLock:
+    """Stat segment optimistic locking"""
 
     def __init__(self, stats):
         self.stats = stats
@@ -283,7 +300,7 @@ class StatsLock():
         self.release()
 
     def acquire(self, blocking=True, timeout=-1):
-        '''Acquire the lock. Await in progress to go false. Record epoch.'''
+        """Acquire the lock. Await in progress to go false. Record epoch."""
         self.epoch = self.stats.epoch
         if timeout > 0:
             start = time.monotonic()
@@ -296,46 +313,49 @@ class StatsLock():
         return True
 
     def release(self):
-        '''Check if data read while locked is valid'''
+        """Check if data read while locked is valid"""
         if self.stats.in_progress or self.stats.epoch != self.epoch:
-            raise IOError('Optimistic lock failed, retry')
+            raise IOError("Optimistic lock failed, retry")
 
     def locked(self):
-        '''Not used'''
+        """Not used"""
 
 
 class StatsCombinedList(list):
-    '''Column slicing for Combined counters list'''
+    """Column slicing for Combined counters list"""
 
     def __getitem__(self, item):
-        '''Supports partial numpy style 2d support. Slice by column [:,1]'''
+        """Supports partial numpy style 2d support. Slice by column [:,1]"""
         if isinstance(item, int):
             return list.__getitem__(self, item)
         return CombinedList([row[item[1]] for row in self])
 
+
 class CombinedList(list):
-    '''Combined Counters 2-dimensional by thread by index of packets/octets'''
+    """Combined Counters 2-dimensional by thread by index of packets/octets"""
 
     def packets(self):
-        '''Return column (2nd dimension). Packets for all threads'''
+        """Return column (2nd dimension). Packets for all threads"""
         return [pair[0] for pair in self]
 
     def octets(self):
-        '''Return column (2nd dimension). Octets for all threads'''
+        """Return column (2nd dimension). Octets for all threads"""
         return [pair[1] for pair in self]
 
     def sum_packets(self):
-        '''Return column (2nd dimension). Sum of all packets for all threads'''
+        """Return column (2nd dimension). Sum of all packets for all threads"""
         return sum(self.packets())
 
     def sum_octets(self):
-        '''Return column (2nd dimension). Sum of all octets for all threads'''
+        """Return column (2nd dimension). Sum of all octets for all threads"""
         return sum(self.octets())
 
+
 class StatsTuple(tuple):
-    '''A Combined vector tuple (packets, octets)'''
+    """A Combined vector tuple (packets, octets)"""
+
     def __init__(self, data):
-        self.dictionary = {'packets': data[0], 'bytes': data[1]}
+        self.dictionary = {"packets": data[0], "bytes": data[1]}
         super().__init__()
 
     def __repr__(self):
@@ -344,28 +364,32 @@ class StatsTuple(tuple):
     def __getitem__(self, item):
         if isinstance(item, int):
             return tuple.__getitem__(self, item)
-        if item == 'packets':
+        if item == "packets":
             return tuple.__getitem__(self, 0)
         return tuple.__getitem__(self, 1)
 
+
 class StatsSimpleList(list):
-    '''Simple Counters 2-dimensional by thread by index of packets'''
+    """Simple Counters 2-dimensional by thread by index of packets"""
 
     def __getitem__(self, item):
-        '''Supports partial numpy style 2d support. Slice by column [:,1]'''
+        """Supports partial numpy style 2d support. Slice by column [:,1]"""
         if isinstance(item, int):
             return list.__getitem__(self, item)
         return SimpleList([row[item[1]] for row in self])
 
+
 class SimpleList(list):
-    '''Simple counter'''
+    """Simple counter"""
 
     def sum(self):
-        '''Sum the vector'''
+        """Sum the vector"""
         return sum(self)
 
-class StatsEntry():
-    '''An individual stats entry'''
+
+class StatsEntry:
+    """An individual stats entry"""
+
     # pylint: disable=unused-argument,no-self-use
 
     def __init__(self, stattype, statvalue):
@@ -386,115 +410,128 @@ class StatsEntry():
             self.function = self.illegal
 
     def illegal(self, stats):
-        '''Invalid or unknown counter type'''
+        """Invalid or unknown counter type"""
         return None
 
     def scalar(self, stats):
-        '''Scalar counter'''
+        """Scalar counter"""
         return self.value
 
     def simple(self, stats):
-        '''Simple counter'''
+        """Simple counter"""
         counter = StatsSimpleList()
-        for threads in StatsVector(stats, self.value, 'P'):
-            clist = [v[0] for v in StatsVector(stats, threads[0], 'Q')]
+        for threads in StatsVector(stats, self.value, "P"):
+            clist = [v[0] for v in StatsVector(stats, threads[0], "Q")]
             counter.append(clist)
         return counter
 
     def combined(self, stats):
-        '''Combined counter'''
+        """Combined counter"""
         counter = StatsCombinedList()
-        for threads in StatsVector(stats, self.value, 'P'):
-            clist = [StatsTuple(cnt) for cnt in StatsVector(stats, threads[0], 'QQ')]
+        for threads in StatsVector(stats, self.value, "P"):
+            clist = [StatsTuple(cnt) for cnt in StatsVector(stats, threads[0], "QQ")]
             counter.append(clist)
         return counter
 
     def name(self, stats):
-        '''Name counter'''
+        """Name counter"""
         counter = []
-        for name in StatsVector(stats, self.value, 'P'):
+        for name in StatsVector(stats, self.value, "P"):
             if name[0]:
                 counter.append(get_string(stats, name[0]))
         return counter
 
-    SYMLINK_FMT1 = Struct('II')
-    SYMLINK_FMT2 = Struct('Q')
+    SYMLINK_FMT1 = Struct("II")
+    SYMLINK_FMT2 = Struct("Q")
+
     def symlink(self, stats):
-        '''Symlink counter'''
+        """Symlink counter"""
         b = self.SYMLINK_FMT2.pack(self.value)
         index1, index2 = self.SYMLINK_FMT1.unpack(b)
         name = stats.directory_by_idx[index1]
-        return stats[name][:,index2]
+        return stats[name][:, index2]
 
     def get_counter(self, stats):
-        '''Return a list of counters'''
+        """Return a list of counters"""
         if stats:
             return self.function(stats)
 
+
 class TestStats(unittest.TestCase):
-    '''Basic statseg tests'''
+    """Basic statseg tests"""
 
     def setUp(self):
-        '''Connect to statseg'''
+        """Connect to statseg"""
         self.stat = VPPStats()
         self.stat.connect()
         self.profile = cProfile.Profile()
         self.profile.enable()
 
     def tearDown(self):
-        '''Disconnect from statseg'''
+        """Disconnect from statseg"""
         self.stat.disconnect()
         profile = Stats(self.profile)
         profile.strip_dirs()
-        profile.sort_stats('cumtime')
+        profile.sort_stats("cumtime")
         profile.print_stats()
         print("\n--->>>")
 
     def test_counters(self):
-        '''Test access to statseg'''
-
-        print('/err/abf-input-ip4/missed', self.stat['/err/abf-input-ip4/missed'])
-        print('/sys/heartbeat', self.stat['/sys/heartbeat'])
-        print('/if/names', self.stat['/if/names'])
-        print('/if/rx-miss', self.stat['/if/rx-miss'])
-        print('/if/rx-miss', self.stat['/if/rx-miss'][1])
-        print('/nat44-ed/out2in/slowpath/drops', self.stat['/nat44-ed/out2in/slowpath/drops'])
+        """Test access to statseg"""
+
+        print("/err/abf-input-ip4/missed", self.stat["/err/abf-input-ip4/missed"])
+        print("/sys/heartbeat", self.stat["/sys/heartbeat"])
+        print("/if/names", self.stat["/if/names"])
+        print("/if/rx-miss", self.stat["/if/rx-miss"])
+        print("/if/rx-miss", self.stat["/if/rx-miss"][1])
+        print(
+            "/nat44-ed/out2in/slowpath/drops",
+            self.stat["/nat44-ed/out2in/slowpath/drops"],
+        )
         with self.assertRaises(KeyError):
-            print('NO SUCH COUNTER', self.stat['foobar'])
-        print('/if/rx', self.stat.get_counter('/if/rx'))
-        print('/err/ethernet-input/no_error',
-              self.stat.get_counter('/err/ethernet-input/no_error'))
+            print("NO SUCH COUNTER", self.stat["foobar"])
+        print("/if/rx", self.stat.get_counter("/if/rx"))
+        print(
+            "/err/ethernet-input/no_error",
+            self.stat.get_counter("/err/ethernet-input/no_error"),
+        )
 
     def test_column(self):
-        '''Test column slicing'''
-
-        print('/if/rx-miss', self.stat['/if/rx-miss'])
-        print('/if/rx', self.stat['/if/rx'])  # All interfaces for thread #1
-        print('/if/rx thread #1', self.stat['/if/rx'][0])  # All interfaces for thread #1
-        print('/if/rx thread #1, interface #1',
-              self.stat['/if/rx'][0][1])  # All interfaces for thread #1
-        print('/if/rx if_index #1', self.stat['/if/rx'][:, 1])
-        print('/if/rx if_index #1 packets', self.stat['/if/rx'][:, 1].packets())
-        print('/if/rx if_index #1 packets', self.stat['/if/rx'][:, 1].sum_packets())
-        print('/if/rx if_index #1 packets', self.stat['/if/rx'][:, 1].octets())
-        print('/if/rx-miss', self.stat['/if/rx-miss'])
-        print('/if/rx-miss if_index #1 packets', self.stat['/if/rx-miss'][:, 1].sum())
-        print('/if/rx if_index #1 packets', self.stat['/if/rx'][0][1]['packets'])
+        """Test column slicing"""
+
+        print("/if/rx-miss", self.stat["/if/rx-miss"])
+        print("/if/rx", self.stat["/if/rx"])  # All interfaces for thread #1
+        print(
+            "/if/rx thread #1", self.stat["/if/rx"][0]
+        )  # All interfaces for thread #1
+        print(
+            "/if/rx thread #1, interface #1", self.stat["/if/rx"][0][1]
+        )  # All interfaces for thread #1
+        print("/if/rx if_index #1", self.stat["/if/rx"][:, 1])
+        print("/if/rx if_index #1 packets", self.stat["/if/rx"][:, 1].packets())
+        print("/if/rx if_index #1 packets", self.stat["/if/rx"][:, 1].sum_packets())
+        print("/if/rx if_index #1 packets", self.stat["/if/rx"][:, 1].octets())
+        print("/if/rx-miss", self.stat["/if/rx-miss"])
+        print("/if/rx-miss if_index #1 packets", self.stat["/if/rx-miss"][:, 1].sum())
+        print("/if/rx if_index #1 packets", self.stat["/if/rx"][0][1]["packets"])
 
     def test_nat44(self):
-        '''Test the nat counters'''
+        """Test the nat counters"""
 
-        print('/nat44-ei/ha/del-event-recv', self.stat['/nat44-ei/ha/del-event-recv'])
-        print('/err/nat44-ei-ha/pkts-processed', self.stat['/err/nat44-ei-ha/pkts-processed'].sum())
+        print("/nat44-ei/ha/del-event-recv", self.stat["/nat44-ei/ha/del-event-recv"])
+        print(
+            "/err/nat44-ei-ha/pkts-processed",
+            self.stat["/err/nat44-ei-ha/pkts-processed"].sum(),
+        )
 
     def test_legacy(self):
-        '''Legacy interface'''
+        """Legacy interface"""
         directory = self.stat.ls(["^/if", "/err/ip4-input", "/sys/node/ip4-input"])
         data = self.stat.dump(directory)
         print(data)
-        print('Looking up sys node')
+        print("Looking up sys node")
         directory = self.stat.ls(["^/sys/node"])
-        print('Dumping sys node')
+        print("Dumping sys node")
         data = self.stat.dump(directory)
         print(data)
         directory = self.stat.ls(["^/foobar"])
@@ -502,18 +539,19 @@ class TestStats(unittest.TestCase):
         print(data)
 
     def test_sys_nodes(self):
-        '''Test /sys/nodes'''
-        counters = self.stat.ls('^/sys/node')
-        print('COUNTERS:', counters)
-        print('/sys/node', self.stat.dump(counters))
-        print('/net/route/to', self.stat['/net/route/to'])
+        """Test /sys/nodes"""
+        counters = self.stat.ls("^/sys/node")
+        print("COUNTERS:", counters)
+        print("/sys/node", self.stat.dump(counters))
+        print("/net/route/to", self.stat["/net/route/to"])
 
     def test_symlink(self):
-        '''Symbolic links'''
-        print('/interface/local0/rx', self.stat['/interfaces/local0/rx'])
-        print('/sys/nodes/unix-epoll-input', self.stat['/nodes/unix-epoll-input/calls'])
+        """Symbolic links"""
+        print("/interface/local0/rx", self.stat["/interfaces/local0/rx"])
+        print("/sys/nodes/unix-epoll-input", self.stat["/nodes/unix-epoll-input/calls"])
+
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     import cProfile
     from pstats import Stats
 
diff --git a/src/vpp-api/python/vpp_papi/vpp_transport_socket.py b/src/vpp-api/python/vpp_papi/vpp_transport_socket.py
index c82b8c365a1..3a8c332a00a 100644
--- a/src/vpp-api/python/vpp_papi/vpp_transport_socket.py
+++ b/src/vpp-api/python/vpp_papi/vpp_transport_socket.py
@@ -9,7 +9,7 @@ import multiprocessing
 import queue
 import logging
 
-logger = logging.getLogger('vpp_papi.transport')
+logger = logging.getLogger("vpp_papi.transport")
 logger.addHandler(logging.NullHandler())
 
 
@@ -26,7 +26,7 @@ class VppTransport:
         self.read_timeout = read_timeout if read_timeout > 0 else None
         self.parent = parent
         self.server_address = server_address
-        self.header = struct.Struct('>QII')
+        self.header = struct.Struct(">QII")
         self.message_table = {}
         # These queues can be accessed async.
         # They are always up, but replaced on connect.
@@ -41,11 +41,10 @@ class VppTransport:
     def msg_thread_func(self):
         while True:
             try:
-                rlist, _, _ = select.select([self.socket,
-                                             self.sque._reader], [], [])
+                rlist, _, _ = select.select([self.socket, self.sque._reader], [], [])
             except socket.error:
                 # Terminate thread
-                logging.error('select failed')
+                logging.error("select failed")
                 self.q.put(None)
                 return
 
@@ -71,8 +70,7 @@ class VppTransport:
                     else:
                         self.parent.msg_handler_async(msg)
                 else:
-                    raise VppTransportSocketIOError(
-                        2, 'Unknown response from select')
+                    raise VppTransportSocketIOError(2, "Unknown response from select")
 
     def connect(self, name, pfx, msg_handler, rx_qlen):
         # TODO: Reorder the actions and add "roll-backs",
@@ -80,7 +78,8 @@ class VppTransport:
 
         if self.message_thread is not None:
             raise VppTransportSocketIOError(
-                1, "PAPI socket transport connect: Need to disconnect first.")
+                1, "PAPI socket transport connect: Need to disconnect first."
+            )
 
         # Create a UDS socket
         self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
@@ -107,19 +106,17 @@ class VppTransport:
         self.message_thread = threading.Thread(target=self.msg_thread_func)
 
         # Initialise sockclnt_create
-        sockclnt_create = self.parent.messages['sockclnt_create']
-        sockclnt_create_reply = self.parent.messages['sockclnt_create_reply']
+        sockclnt_create = self.parent.messages["sockclnt_create"]
+        sockclnt_create_reply = self.parent.messages["sockclnt_create_reply"]
 
-        args = {'_vl_msg_id': 15,
-                'name': name,
-                'context': 124}
+        args = {"_vl_msg_id": 15, "name": name, "context": 124}
         b = sockclnt_create.pack(args)
         self.write(b)
         msg = self._read()
         hdr, length = self.parent.header.unpack(msg, 0)
         if hdr.msgid != 16:
             # TODO: Add first numeric argument.
-            raise VppTransportSocketIOError('Invalid reply message')
+            raise VppTransportSocketIOError("Invalid reply message")
 
         r, length = sockclnt_create_reply.unpack(msg)
         self.socket_index = r.index
@@ -184,7 +181,7 @@ class VppTransport:
     def write(self, buf):
         """Send a binary-packed message to VPP."""
         if not self.connected:
-            raise VppTransportSocketIOError(1, 'Not connected')
+            raise VppTransportSocketIOError(1, "Not connected")
 
         # Send header
         header = self.header.pack(0, len(buf), 0)
@@ -192,8 +189,7 @@ class VppTransport:
             self.socket.sendall(header)
             self.socket.sendall(buf)
         except socket.error as err:
-            raise VppTransportSocketIOError(1, 'Sendall error: {err!r}'.format(
-                err=err))
+            raise VppTransportSocketIOError(1, "Sendall error: {err!r}".format(err=err))
 
     def _read_fixed(self, size):
         """Repeat receive until fixed size is read. Return empty on error."""
@@ -223,11 +219,11 @@ class VppTransport:
         msg = self._read_fixed(hdrlen)
         if hdrlen == len(msg):
             return msg
-        raise VppTransportSocketIOError(1, 'Unknown socket read error')
+        raise VppTransportSocketIOError(1, "Unknown socket read error")
 
     def read(self, timeout=None):
         if not self.connected:
-            raise VppTransportSocketIOError(1, 'Not connected')
+            raise VppTransportSocketIOError(1, "Not connected")
         if timeout is None:
             timeout = self.read_timeout
         try: