  python primitives.
  2. The process of marshalling between python primitives and request and
  response content is handled by parsers and renderers.
  """
  from django.core.exceptions import ImproperlyConfigured
  from django.core.exceptions import ValidationError as DjangoValidationError
  from django.db import models
  from django.db.models.fields import FieldDoesNotExist
  from django.utils import six
  from django.utils.translation import ugettext_lazy as _
  from rest_framework.compat import OrderedDict
 
</s> remove from django.utils import six
 </s> add  </s> remove from rest_framework.compat import OrderedDict
from rest_framework.exceptions import ValidationError
from rest_framework.fields import empty, set_value, Field, SkipField
from rest_framework.settings import api_settings
from rest_framework.utils import html, model_meta, representation
 </s> add from rest_framework.utils import model_meta </s> remove `ModelSerializer` class and an equivelent explicit `Serializer` class.
 </s> add `ModelSerializer` class and an equivalent explicit `Serializer` class. </s> remove import copy
import inspect
import warnings
 </s> add  </s> remove     don't need to dig into the implemention.
 </s> add     don't need to dig into the implementation.
import warnings

  python primitives.
  2. The process of marshalling between python primitives and request and
  response content is handled by parsers and renderers.
  """
import warnings

import warnings

  from django.db import models
  from django.db.models.fields import FieldDoesNotExist
  from django.utils import six
  from django.utils.translation import ugettext_lazy as _
  from rest_framework.compat import OrderedDict
keep keep keep keep replace replace keep keep keep keep keep
 Removed unused imports, pep8 fixes, typo fixes 
rest_framework/serializers.py