          self.assertIsInstance(food_no_default_manager_state.managers[1][1], FoodManager)
  
          self.assertEqual([name for name, mgr in food_order_manager_state.managers],
                           ['food_mgr1', 'food_mgr2'])
          self.assertTrue(all(isinstance(name, six.text_type) for name, mgr in food_order_manager_state.managers))
          self.assertEqual([mgr.args for name, mgr in food_order_manager_state.managers],
                           [('a', 'b', 1, 2), ('x', 'y', 3, 4)])
  
      def test_custom_default_manager_added_to_the_model_state(self):
          """
 
</s> remove         self.assertTrue(all(isinstance(mgr.name, six.text_type) for mgr in Food._meta.managers))
 </s> add         self.assertTrue(all(isinstance(mgr.name, str) for mgr in Food._meta.managers)) </s> remove         if isinstance(value, six.string_types):
 </s> add         if isinstance(value, str): </s> remove                 if isinstance(items, six.string_types):
 </s> add                 if isinstance(items, str): </s> remove     if isinstance(file_h, six.string_types):
 </s> add     if isinstance(file_h, str): </s> remove             lists = [[six.text_type(r) for r in a.first_book.read_by.all()]
 </s> add             lists = [[str(r) for r in a.first_book.read_by.all()]
        self.assertTrue(all(isinstance(name, str) for name, mgr in food_order_manager_state.managers))
          self.assertIsInstance(food_no_default_manager_state.managers[1][1], FoodManager)
  
          self.assertEqual([name for name, mgr in food_order_manager_state.managers],
                           ['food_mgr1', 'food_mgr2'])
        self.assertTrue(all(isinstance(name, str) for name, mgr in food_order_manager_state.managers))
          self.assertEqual([mgr.args for name, mgr in food_order_manager_state.managers],
                           [('a', 'b', 1, 2), ('x', 'y', 3, 4)])
  
      def test_custom_default_manager_added_to_the_model_state(self):
          """
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/migrations/test_state.py