def undefine(self):
        """Undefine the MessageHandler.

        Python equivalent of the CLIPS undefmessage-handler command.

        The object becomes unusable after this method has been called.

        """
        if lib.EnvUndefmessageHandler(self._env, self._cls, self._idx) != 1:
            raise CLIPSError(self._env)

        self._env = None
Undefine the MessageHandler.

        Python equivalent of the CLIPS undefmessage-handler command.

        The object becomes unusable after this method has been called.