  from django.db import models
  from django.utils import six
  from rest_framework.compat import django_filters, guardian, get_model_name
  from rest_framework.settings import api_settings
  from functools import reduce
  import operator
  
  FilterSet = django_filters and django_filters.FilterSet or None
  
  
  class BaseFilterBackend(object):
 
</s> remove from rest_framework.compat import django_filters, guardian, get_model_name
 </s> add from django.db import models
from django.core.exceptions import ImproperlyConfigured
 </s> remove from django.core.exceptions import ImproperlyConfigured
from django.db import models
 </s> add import operator
from functools import reduce
 </s> remove import inspect
 </s> add 
from rest_framework.compat import django_filters, guardian, get_model_name

  from django.db import models
  from django.utils import six
  from rest_framework.compat import django_filters, guardian, get_model_name
  from rest_framework.settings import api_settings
from rest_framework.compat import django_filters, guardian, get_model_name

from rest_framework.compat import django_filters, guardian, get_model_name

  
  FilterSet = django_filters and django_filters.FilterSet or None
  
  
  class BaseFilterBackend(object):
keep keep keep keep replace replace keep keep keep keep keep
 Cleanup import following PEP 8 style guide 
rest_framework/filters.py