Fixed three small flake8 violations.

django/db/migrations/state.py

@@ -166,7 +166,7 @@ class ModelState(object):
         # __bases__ we may end up with duplicates and ordering issues, we
         # therefore discard any duplicates and reorder the bases according
         # to their index in the MRO.
-        flattened_bases = sorted(set(flatten_bases(model)), key=lambda x:model.__mro__.index(x))
+        flattened_bases = sorted(set(flatten_bases(model)), key=lambda x: model.__mro__.index(x))
 
         # Make our record
         bases = tuple(

tests/migrations/test_operations.py

@@ -582,6 +582,7 @@ class OperationTests(MigrationTestBase):
         self.assertEqual(project_state.render().get_model("test_runpython", "Pony").objects.count(), 6)
         self.assertEqual(project_state.render().get_model("test_runpython", "ShetlandPony").objects.count(), 2)
 
+
 class MigrateNothingRouter(object):
     """
     A router that sends all writes to the other database.