def test_clear(self):
        """
        L{Tag.clear} removes all children from a tag, but leaves its attributes
        in place.
        """
        tag = proto("these are", "children", "cool", andSoIs='this-attribute')
        tag.clear()
        self.assertEqual(tag.children, [])
        self.assertEqual(tag.attributes, {'andSoIs': 'this-attribute'})

        L{Tag.clear} removes all children from a tag, but leaves its attributes
        in place.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_stan.py