  from django.utils import six, timezone
  from django.utils.functional import cached_property
  from django.utils.translation import ugettext_lazy as _
  
  from rest_framework.compat import Mapping, postgres_fields, unicode_to_repr
  from rest_framework.exceptions import ErrorDetail, ValidationError
  from rest_framework.fields import get_error_detail, set_value
  from rest_framework.settings import api_settings
  from rest_framework.utils import html, model_meta, representation
  from rest_framework.utils.field_mapping import (
 
</s> remove from django.utils import six, timezone
 </s> add from django.utils import timezone </s> remove from django.utils import six, translation
 </s> add from django.utils import translation </s> remove from rest_framework.compat import unicode_to_repr
 </s> add  </s> remove # -*- coding: utf-8 -*-
from __future__ import unicode_literals

 </s> add  </s> remove from django.utils import six, timezone
 </s> add from django.utils import timezone
from rest_framework.compat import Mapping, postgres_fields
  from django.utils import six, timezone
  from django.utils.functional import cached_property
  from django.utils.translation import ugettext_lazy as _
  
from rest_framework.compat import Mapping, postgres_fields
  from rest_framework.exceptions import ErrorDetail, ValidationError
  from rest_framework.fields import get_error_detail, set_value
  from rest_framework.settings import api_settings
  from rest_framework.utils import html, model_meta, representation
  from rest_framework.utils.field_mapping import (
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> 
rest_framework/serializers.py