  import pytz
  from django.core.exceptions import ValidationError as DjangoValidationError
  from django.http import QueryDict
  from django.test import TestCase, override_settings
  from django.utils import six
  from django.utils.timezone import activate, deactivate, override, utc
  
  import rest_framework
  from rest_framework import exceptions, serializers
  from rest_framework.compat import ProhibitNullCharactersValidator
 
</s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add  </s> remove from rest_framework.compat import postgres_fields, unicode_repr
 </s> add from rest_framework.compat import postgres_fields </s> remove from __future__ import unicode_literals

 </s> add 
  import pytz
  from django.core.exceptions import ValidationError as DjangoValidationError
  from django.http import QueryDict
  from django.test import TestCase, override_settings

  from django.utils.timezone import activate, deactivate, override, utc
  
  import rest_framework
  from rest_framework import exceptions, serializers
  from rest_framework.compat import ProhibitNullCharactersValidator
keep keep keep keep replace keep keep keep keep keep
 Dropped Python 2 compatibility. (#6615)

Thanks to Jon Dufresne (@jdufresne) for review.

Co-authored-by: Asif Saif Uddin <auvipy@gmail.com>
Co-authored-by: Rizwan Mansuri <Rizwan@webbyfox.com> 
tests/test_fields.py