diff --git a/test/util.py b/test/util.py
index 5ce8407..fc0ebd7 100644
--- a/test/util.py
+++ b/test/util.py
@@ -2,18 +2,19 @@
 
 import abc
 import socket
+from socket import AF_INET6
 import six
 import sys
 import os.path
-from scapy.utils6 import in6_mactoifaceid
 
 from scapy.layers.l2 import Ether
-from scapy.packet import Raw
 from scapy.layers.inet import IP
 from scapy.layers.inet6 import IPv6, IPv6ExtHdrFragment, IPv6ExtHdrRouting,\
     IPv6ExtHdrHopByHop
+from scapy.packet import Raw
 from scapy.utils import hexdump
-from socket import AF_INET6
+from scapy.utils6 import in6_mactoifaceid
+
 from io import BytesIO
 from vpp_papi import mac_pton
 
@@ -54,6 +55,7 @@
             for ip in ip4_range(ip4, s, e))
 
 
+# wrapper around scapy library function.
 def mk_ll_addr(mac):
     euid = in6_mactoifaceid(mac)
     addr = "fe80::" + euid