def METHOD_NAME(self) -> None:
    """
    The response to a challenge without a realm uses the host part of the
    JID as the realm.
    """
    challenge = b'nonce="1234",qop="auth",charset=utf-8,algorithm=md5-sess'
    directives = self.mechanism._parse(self.mechanism.getResponse(challenge))
    self.assertEqual(directives[b"realm"], b"example.org")