diff --git a/graphene_django/rest_framework/serializer_converter.py b/graphene_django/rest_framework/serializer_converter.py
index 6e5ebb0..caeb7dd 100644
--- a/graphene_django/rest_framework/serializer_converter.py
+++ b/graphene_django/rest_framework/serializer_converter.py
@@ -153,5 +153,5 @@ def convert_serializer_field_to_list_of_enum(field):
 @get_graphene_type_from_serializer_field.register(serializers.ChoiceField)
 def convert_serializer_field_to_enum(field):
     # enums require a name
-    name = field.field_name or field.source or 'Choices'
+    name = field.field_name or field.source or "Choices"
     return convert_choices_to_named_enum_with_descriptions(name, field.choices)
diff --git a/graphene_django/rest_framework/tests/test_field_converter.py b/graphene_django/rest_framework/tests/test_field_converter.py
index d99d5f0..82f5b63 100644
--- a/graphene_django/rest_framework/tests/test_field_converter.py
+++ b/graphene_django/rest_framework/tests/test_field_converter.py
@@ -61,8 +61,12 @@ def test_should_url_convert_string():
 
 
 def test_should_choice_convert_enum():
-    field = assert_conversion(serializers.ChoiceField, graphene.Enum,
-        choices=[('h', 'Hello'), ('w', 'World')], source='word')
+    field = assert_conversion(
+        serializers.ChoiceField,
+        graphene.Enum,
+        choices=[("h", "Hello"), ("w", "World")],
+        source="word",
+    )
     assert field._meta.enum.__members__["H"].value == "h"
     assert field._meta.enum.__members__["H"].description == "Hello"
     assert field._meta.enum.__members__["W"].value == "w"