def test_lenientParentSingle(self):
        """
        Test that the C{parentNode} attribute is set to a meaningful value
        when we parse an HTML document that has a non-Element root node.
        """
        s = "Hello"
        d = microdom.parseString(s, beExtremelyLenient=1)
        self.assertIdentical(d.documentElement,
                             d.documentElement.firstChild().parentNode)

        Test that the C{parentNode} attribute is set to a meaningful value
        when we parse an HTML document that has a non-Element root node.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_xml.py