  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
  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
  from rest_framework.utils.field_mapping import (
      get_url_kwargs, get_field_kwargs,
      get_relation_kwargs, get_nested_relation_kwargs,
      ClassLookupDict
  )
 
</s> remove from django.utils import six
 </s> add  </s> remove from django.core.exceptions import ImproperlyConfigured
from django.core.exceptions import ValidationError as DjangoValidationError
 </s> add import warnings
 </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             'The `.create()` method does not suport nested writable fields '
 </s> add             'The `.create()` method does not support nested writable fields '
from rest_framework.utils import model_meta
  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.utils import model_meta
from rest_framework.utils import model_meta
from rest_framework.utils import model_meta
from rest_framework.utils import model_meta
from rest_framework.utils import model_meta
  from rest_framework.utils.field_mapping import (
      get_url_kwargs, get_field_kwargs,
      get_relation_kwargs, get_nested_relation_kwargs,
      ClassLookupDict
  )
keep keep keep keep replace replace replace replace replace keep keep keep keep keep
 Removed unused imports, pep8 fixes, typo fixes 
rest_framework/serializers.py