diff --git a/test/test_nat66.py b/test/test_nat66.py
index 02b2882..f3bec78 100644
--- a/test/test_nat66.py
+++ b/test/test_nat66.py
@@ -10,15 +10,32 @@
 import scapy.compat
 from framework import VppTestCase, VppTestRunner
 from ipfix import IPFIX, Set, Template, Data, IPFIXDecoder
-from scapy.all import bind_layers, Packet, ByteEnumField, ShortField, \
-    IPField, IntField, LongField, XByteField, FlagsField, FieldLenField, \
-    PacketListField
+from scapy.all import (
+    bind_layers,
+    Packet,
+    ByteEnumField,
+    ShortField,
+    IPField,
+    IntField,
+    LongField,
+    XByteField,
+    FlagsField,
+    FieldLenField,
+    PacketListField,
+)
 from scapy.data import IP_PROTOS
 from scapy.layers.inet import IP, TCP, UDP, ICMP
 from scapy.layers.inet import IPerror, TCPerror, UDPerror, ICMPerror
 from scapy.layers.inet6 import ICMPv6DestUnreach, IPerror6, IPv6ExtHdrFragment
-from scapy.layers.inet6 import IPv6, ICMPv6EchoRequest, ICMPv6EchoReply, \
-    ICMPv6ND_NS, ICMPv6ND_NA, ICMPv6NDOptDstLLAddr, fragment6
+from scapy.layers.inet6 import (
+    IPv6,
+    ICMPv6EchoRequest,
+    ICMPv6EchoReply,
+    ICMPv6ND_NS,
+    ICMPv6ND_NA,
+    ICMPv6NDOptDstLLAddr,
+    fragment6,
+)
 from scapy.layers.l2 import Ether, ARP, GRE
 from scapy.packet import Raw
 from syslog_rfc5424_parser import SyslogMessage, ParseError
@@ -32,13 +49,13 @@
 
 
 class TestNAT66(VppTestCase):
-    """ NAT66 Test Cases """
+    """NAT66 Test Cases"""
 
     @classmethod
     def setUpClass(cls):
         super(TestNAT66, cls).setUpClass()
 
-        cls.nat_addr = 'fd01:ff::2'
+        cls.nat_addr = "fd01:ff::2"
         cls.create_pg_interfaces(range(2))
         cls.interfaces = list(cls.pg_interfaces)
 
@@ -67,34 +84,45 @@
             self.plugin_disable()
 
     def test_static(self):
-        """ 1:1 NAT66 test """
+        """1:1 NAT66 test"""
         flags = self.config_flags.NAT_IS_INSIDE
-        self.vapi.nat66_add_del_interface(is_add=1, flags=flags,
-                                          sw_if_index=self.pg0.sw_if_index)
-        self.vapi.nat66_add_del_interface(is_add=1,
-                                          sw_if_index=self.pg1.sw_if_index)
+        self.vapi.nat66_add_del_interface(
+            is_add=1, flags=flags, sw_if_index=self.pg0.sw_if_index
+        )
+        self.vapi.nat66_add_del_interface(is_add=1, sw_if_index=self.pg1.sw_if_index)
         self.vapi.nat66_add_del_static_mapping(
             local_ip_address=self.pg0.remote_ip6,
             external_ip_address=self.nat_addr,
-            is_add=1)
+            is_add=1,
+        )
 
         # in2out
         pkts = []
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6) /
-             TCP())
+        p = (
+            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+            / IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
+            / TCP()
+        )
         pkts.append(p)
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6) /
-             UDP())
+        p = (
+            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+            / IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
+            / UDP()
+        )
         pkts.append(p)
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6) /
-             ICMPv6EchoRequest())
+        p = (
+            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+            / IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
+            / ICMPv6EchoRequest()
+        )
         pkts.append(p)
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6) /
-             GRE() / IP() / TCP())
+        p = (
+            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+            / IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
+            / GRE()
+            / IP()
+            / TCP()
+        )
         pkts.append(p)
         self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
@@ -112,21 +140,31 @@
 
         # out2in
         pkts = []
-        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
-             IPv6(src=self.pg1.remote_ip6, dst=self.nat_addr) /
-             TCP())
+        p = (
+            Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac)
+            / IPv6(src=self.pg1.remote_ip6, dst=self.nat_addr)
+            / TCP()
+        )
         pkts.append(p)
-        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
-             IPv6(src=self.pg1.remote_ip6, dst=self.nat_addr) /
-             UDP())
+        p = (
+            Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac)
+            / IPv6(src=self.pg1.remote_ip6, dst=self.nat_addr)
+            / UDP()
+        )
         pkts.append(p)
-        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
-             IPv6(src=self.pg1.remote_ip6, dst=self.nat_addr) /
-             ICMPv6EchoReply())
+        p = (
+            Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac)
+            / IPv6(src=self.pg1.remote_ip6, dst=self.nat_addr)
+            / ICMPv6EchoReply()
+        )
         pkts.append(p)
-        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
-             IPv6(src=self.pg1.remote_ip6, dst=self.nat_addr) /
-             GRE() / IP() / TCP())
+        p = (
+            Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac)
+            / IPv6(src=self.pg1.remote_ip6, dst=self.nat_addr)
+            / GRE()
+            / IP()
+            / TCP()
+        )
         pkts.append(p)
         self.pg1.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
@@ -146,21 +184,26 @@
         self.assertEqual(sm[0].total_pkts, 8)
 
     def test_check_no_translate(self):
-        """ NAT66 translate only when egress interface is outside interface """
+        """NAT66 translate only when egress interface is outside interface"""
         flags = self.config_flags.NAT_IS_INSIDE
-        self.vapi.nat66_add_del_interface(is_add=1, flags=flags,
-                                          sw_if_index=self.pg0.sw_if_index)
-        self.vapi.nat66_add_del_interface(is_add=1, flags=flags,
-                                          sw_if_index=self.pg1.sw_if_index)
+        self.vapi.nat66_add_del_interface(
+            is_add=1, flags=flags, sw_if_index=self.pg0.sw_if_index
+        )
+        self.vapi.nat66_add_del_interface(
+            is_add=1, flags=flags, sw_if_index=self.pg1.sw_if_index
+        )
         self.vapi.nat66_add_del_static_mapping(
             local_ip_address=self.pg0.remote_ip6,
             external_ip_address=self.nat_addr,
-            is_add=1)
+            is_add=1,
+        )
 
         # in2out
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6) /
-             UDP())
+        p = (
+            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+            / IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
+            / UDP()
+        )
         self.pg0.add_stream([p])
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
@@ -174,5 +217,5 @@
             raise
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main(testRunner=VppTestRunner)