  from django.http import Http404
  from django.utils.encoding import force_text
  from rest_framework import exceptions, serializers
  from rest_framework.compat import OrderedDict
  from rest_framework.request import clone_request
  from rest_framework.utils.field_mapping import ClassLookupDict
  
 
</s> remove from django.core.exceptions import PermissionDenied
 </s> add  </s> remove from rest_framework.request import is_form_media_type, override_method
from rest_framework.utils import encoders
 </s> add  </s> remove from django.utils.translation import ugettext_lazy as _
 </s> add from django.core.exceptions import PermissionDenied </s> remove from rest_framework import HTTP_HEADER_ENCODING
from rest_framework import exceptions
 </s> add from rest_framework import exceptions, HTTP_HEADER_ENCODING
from django.core.exceptions import PermissionDenied

  from django.http import Http404
  from django.utils.encoding import force_text
from django.core.exceptions import PermissionDenied

  from rest_framework import exceptions, serializers
  from rest_framework.compat import OrderedDict
  from rest_framework.request import clone_request
  from rest_framework.utils.field_mapping import ClassLookupDict
  
keep add keep keep keep keep keep
 Cleanup import following PEP 8 style guide 
rest_framework/metadata.py