          else:
              if not result:
                  standardMsg = '%s != %s' % (safe_repr(xml1, True), safe_repr(xml2, True))
                  diff = ('\n' + '\n'.join(
                      difflib.ndiff(
                          six.text_type(xml1).splitlines(),
                          six.text_type(xml2).splitlines(),
                      )
                  ))
                  standardMsg = self._truncateMessage(standardMsg, diff)
                  self.fail(self._formatMessage(msg, standardMsg))
  
      def assertXMLNotEqual(self, xml1, xml2, msg=None):
 
</s> remove                 six.text_type(dom1).splitlines(),
                six.text_type(dom2).splitlines(),
 </s> add                 str(dom1).splitlines(), str(dom2).splitlines(), </s> remove         ', '.join(six.text_type(arg) for arg in [one, two] + list(args))
 </s> add         ', '.join(str(arg) for arg in [one, two] + list(args)) </s> remove         ', '.join(six.text_type(arg) for arg in [one, two] + list(args)),
 </s> add         ', '.join(str(arg) for arg in [one, two] + list(args)), </s> remove         if isinstance(self.remote_field.model, six.string_types):
 </s> add         if isinstance(self.remote_field.model, str): </s> remove             if isinstance(self.remote_field.through, six.string_types):
 </s> add             if isinstance(self.remote_field.through, str):
                    difflib.ndiff(xml1.splitlines(), xml2.splitlines())
          else:
              if not result:
                  standardMsg = '%s != %s' % (safe_repr(xml1, True), safe_repr(xml2, True))
                  diff = ('\n' + '\n'.join(
                    difflib.ndiff(xml1.splitlines(), xml2.splitlines())
                    difflib.ndiff(xml1.splitlines(), xml2.splitlines())
                    difflib.ndiff(xml1.splitlines(), xml2.splitlines())
                    difflib.ndiff(xml1.splitlines(), xml2.splitlines())
                  ))
                  standardMsg = self._truncateMessage(standardMsg, diff)
                  self.fail(self._formatMessage(msg, standardMsg))
  
      def assertXMLNotEqual(self, xml1, xml2, msg=None):
keep keep keep keep replace replace replace replace keep keep keep keep keep
 Refs #23919 -- Removed six.<various>_types usage

Thanks Tim Graham and Simon Charette for the reviews. 
django/test/testcases.py