          self.assertEqual(lst, lst2)
  
          qs = BookWithYear.objects.prefetch_related('aged_authors')
          with self.assertNumQueries(2):
              lst = [[six.text_type(author) for author in book.aged_authors.all()] for book in qs]
          qs = BookWithYear.objects.all()
          lst2 = [[six.text_type(author) for author in book.aged_authors.all()] for book in qs]
          self.assertEqual(lst, lst2)
  
      def test_parent_link_prefetch(self):
 
</s> remove         lst2 = [[six.text_type(author) for author in book.aged_authors.all()] for book in qs]
 </s> add         lst2 = [[str(author) for author in book.aged_authors.all()] for book in qs] </s> remove         lst2 = [[six.text_type(book) for book in author.books_with_year.all()] for author in qs]
 </s> add         lst2 = [[str(book) for book in author.books_with_year.all()] for author in qs] </s> remove             lst = [[six.text_type(book) for book in author.books_with_year.all()] for author in qs]
 </s> add             lst = [[str(book) for book in author.books_with_year.all()] for author in qs] </s> remove             addresses = [[six.text_type(address) for address in obj.addresses.all()] for obj in qs]
        self.assertEqual(addresses, [[six.text_type(self.author_address)], [], []])
 </s> add             addresses = [[str(address) for address in obj.addresses.all()] for obj in qs]
        self.assertEqual(addresses, [[str(self.author_address)], [], []]) </s> remove                 [six.text_type(i_like) for i_like in author.favorite_authors.all()],
                [six.text_type(likes_me) for likes_me in author.favors_me.all()]
 </s> add                 [str(i_like) for i_like in author.favorite_authors.all()],
                [str(likes_me) for likes_me in author.favors_me.all()]
            lst = [[str(author) for author in book.aged_authors.all()] for book in qs]
          self.assertEqual(lst, lst2)
  
          qs = BookWithYear.objects.prefetch_related('aged_authors')
          with self.assertNumQueries(2):
            lst = [[str(author) for author in book.aged_authors.all()] for book in qs]
          qs = BookWithYear.objects.all()
          lst2 = [[six.text_type(author) for author in book.aged_authors.all()] for book in qs]
          self.assertEqual(lst, lst2)
  
      def test_parent_link_prefetch(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/prefetch_related/tests.py