      def test_non_string_input(self):
          self.assertEqual(slugify(123), '123')
  
      def test_slugify_lazy_string(self):
          lazy_str = lazy(lambda string: force_text(string), six.text_type)
          self.assertEqual(
              slugify(lazy_str(' Jack & Jill like numbers 1,2,3 and 4 and silly characters ?%.$!/')),
              'jack-jill-like-numbers-123-and-4-and-silly-characters',
          )
 
</s> remove         add_html = lazy(lambda string: string + 'special characters > here', six.text_type)
 </s> add         add_html = lazy(lambda string: string + 'special characters > here', str) </s> remove         add_header = lazy(lambda string: 'Header\n\n' + string, six.text_type)
 </s> add         add_header = lazy(lambda string: 'Header\n\n' + string, str) </s> remove         append_script = lazy(lambda string: r'<script>this</script>' + string, six.text_type)
 </s> add         append_script = lazy(lambda string: r'<script>this</script>' + string, str) </s> remove         prepend_www = lazy(lambda url: 'www.' + url, six.text_type)
 </s> add         prepend_www = lazy(lambda url: 'www.' + url, str) </s> remove                 not isinstance(self.remote_field.model, six.string_types) and
 </s> add                 not isinstance(self.remote_field.model, str) and
        lazy_str = lazy(lambda string: force_text(string), str)
      def test_non_string_input(self):
          self.assertEqual(slugify(123), '123')
  
      def test_slugify_lazy_string(self):
        lazy_str = lazy(lambda string: force_text(string), str)
          self.assertEqual(
              slugify(lazy_str(' Jack & Jill like numbers 1,2,3 and 4 and silly characters ?%.$!/')),
              'jack-jill-like-numbers-123-and-4-and-silly-characters',
          )
keep keep keep keep replace keep keep keep keep
 Refs #23919 -- Removed six.<various>_types usage

Thanks Tim Graham and Simon Charette for the reviews. 
tests/template_tests/filter_tests/test_slugify.py