[common][serializers] six import cleanup

beat/web/common/serializers.py

@@ -29,6 +29,7 @@ from django.conf import settings
 
 from django.core.exceptions import ValidationError
 from django.contrib.auth.models import User
+from django.utils import six
 
 from rest_framework import serializers
 
@@ -45,7 +46,6 @@ import difflib
 
 import ast
 
-import six
 
 #----------------------------------------------------------