  from django.core.exceptions import FieldError, ValidationError
  from django.db import connection, models
  from django.test import SimpleTestCase, TestCase
  from django.test.utils import CaptureQueriesContext, isolate_apps
  from django.utils import six
  
  from .models import (
      Base, Chef, CommonInfo, GrandChild, GrandParent, ItalianRestaurant,
      MixinModel, ParkingLot, Place, Post, Restaurant, Student, SubBase,
      Supplier, Title, Worker,
 
</s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add 
  from django.core.exceptions import FieldError, ValidationError
  from django.db import connection, models
  from django.test import SimpleTestCase, TestCase
  from django.test.utils import CaptureQueriesContext, isolate_apps

  
  from .models import (
      Base, Chef, CommonInfo, GrandChild, GrandParent, ItalianRestaurant,
      MixinModel, ParkingLot, Place, Post, Restaurant, Student, SubBase,
      Supplier, Title, Worker,
keep keep keep keep replace keep keep keep keep keep
 Refs #23919 -- Removed six.<various>_types usage

Thanks Tim Graham and Simon Charette for the reviews. 
tests/model_inheritance/tests.py