diff --git a/graphene/types/tests/test_definition.py b/graphene/types/tests/test_definition.py
index 83f6792d..898fac71 100644
--- a/graphene/types/tests/test_definition.py
+++ b/graphene/types/tests/test_definition.py
@@ -316,12 +316,13 @@ def test_does_not_mutate_passed_field_definitions():
 
     assert TestInputObject1._meta.fields == TestInputObject2._meta.fields
 
+
 def test_graphene_graphql_type_can_be_copied():
     class Query(ObjectType):
         field = String()
 
         def resolve_field(self, info):
-            return ''
+            return ""
 
     schema = Schema(query=Query)
     query_type_copy = copy.copy(schema.graphql_schema.query_type)