def test_getRawHeadersWithDefaultMatchingValue(self):
        """
        If the object passed as the value list to L{Headers.setRawHeaders}
        is later passed as a default to L{Headers.getRawHeaders}, the
        result nevertheless contains encoded values.
        """
        h = Headers()
        default = [u"value"]
        h.setRawHeaders(b"key", default)
        self.assertIsInstance(h.getRawHeaders(b"key", default)[0], bytes)
        self.assertEqual(h.getRawHeaders(b"key", default), [b"value"])

        If the object passed as the value list to L{Headers.setRawHeaders}
        is later passed as a default to L{Headers.getRawHeaders}, the
        result nevertheless contains encoded values.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http_headers.py