style: some of the suggestions from flake8
diff --git a/serial/tools/hexlify_codec.py b/serial/tools/hexlify_codec.py
index fac85db..6d42080 100644
--- a/serial/tools/hexlify_codec.py
+++ b/serial/tools/hexlify_codec.py
@@ -15,8 +15,8 @@
 
 HEXDIGITS = '0123456789ABCDEF'
 
-### Codec APIs
 
+# Codec APIs
 
 def hex_encode(input, errors='strict'):
     return (serial.to_bytes([int(h, 16) for h in input.split()]), len(input))
@@ -84,7 +84,8 @@
     pass
 
 
-### encodings module API
+# encodings module API
+
 def getregentry():
     return codecs.CodecInfo(
         name='hexlify',