def test_dynamicChildren(self):
        """
        L{Resource.getChildWithDefault} delegates to L{Resource.getChild} when
        the requested path is not associated with any static child.
        """
        path = b"foo"
        request = DummyRequest([])
        resource = DynamicChildren()
        child = resource.getChildWithDefault(path, request)
        self.assertIsInstance(child, DynamicChild)
        self.assertEqual(child.path, path)
        self.assertIdentical(child.request, request)

        L{Resource.getChildWithDefault} delegates to L{Resource.getChild} when
        the requested path is not associated with any static child.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_resource.py