diff --git a/rest_framework/tests/serializer.py b/rest_framework/tests/serializer.py
index e85323e0c..ee415eeab 100644
--- a/rest_framework/tests/serializer.py
+++ b/rest_framework/tests/serializer.py
@@ -954,11 +954,12 @@ class SerializerPickleTests(TestCase):
         pickle.dumps(InnerPersonSerializer(Person(name="Noah", age=950)).data)
 
     def test_getstate_method_should_not_return_none(self):
-        '''Regression test for 
+        """
+        Regression test for
         https://github.com/tomchristie/django-rest-framework/issues/645
-        '''
-        d = serializers.DictWithMetadata({1:1})
-        self.assertEqual(d.__getstate__(), serializers.SortedDict({1:1}))
+        """
+        d = serializers.DictWithMetadata({1: 1})
+        self.assertEqual(d.__getstate__(), serializers.SortedDict({1: 1}))
 
 
 class DepthTest(TestCase):