  from django.core.exceptions import ImproperlyConfigured
  from django.core.handlers.wsgi import WSGIHandler
  from django.test import override_settings, testcases
  from django.test.client import Client as DjangoClient
  from django.test.client import RequestFactory as DjangoRequestFactory
  from django.test.client import ClientHandler
  from django.utils import six
  from django.utils.encoding import force_bytes
  from django.utils.http import urlencode
  
 
</s> remove from django.core.exceptions import ValidationError as DjangoValidationError
 </s> add 
  from django.core.exceptions import ImproperlyConfigured
  from django.core.handlers.wsgi import WSGIHandler
  from django.test import override_settings, testcases
  from django.test.client import Client as DjangoClient

  from django.test.client import ClientHandler
  from django.utils import six
  from django.utils.encoding import force_bytes
  from django.utils.http import urlencode
  
keep keep keep keep replace keep keep keep keep keep
 Upgrade isort (#5817)

* Fix isort

* runtests: add --diff to ISORT_ARGS

* requirements-codestyle: bump isort to 4.3.3

* isort: move config to setup.cfg 
rest_framework/test.py