def test_rawHeadersTypeChecking(self):
        """
        L{Headers.setRawHeaders} requires values to be of type list.
        """
        h = Headers()
        self.assertRaises(TypeError, h.setRawHeaders, u'key', {u'Foo': u'bar'})

        L{Headers.setRawHeaders} requires values to be of type list.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http_headers.py