def test_unsupported(self):
        """
        A L{WSGIResource} cannot have L{IResource} children.  Its
        C{getChildWithDefault} and C{putChild} methods raise L{RuntimeError}.
        """
        self.assertRaises(
            RuntimeError,
            self.resource.getChildWithDefault,
            b"foo", Request(DummyChannel(), False))
        self.assertRaises(
            RuntimeError,
            self.resource.putChild,
            b"foo", Resource())

        A L{WSGIResource} cannot have L{IResource} children.  Its
        C{getChildWithDefault} and C{putChild} methods raise L{RuntimeError}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_wsgi.py