def test_namespaceDelete(self):
        """
        Test that C{toxml} can support xml structures that remove namespaces.
        """
        s1 = ('<?xml version="1.0"?><html xmlns="http://www.w3.org/TR/REC-html40">'
              '<body xmlns=""></body></html>')
        s2 = microdom.parseString(s1).toxml()
        self.assertEqual(s1, s2)

        Test that C{toxml} can support xml structures that remove namespaces.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_xml.py