def stop_responding(server_name, challenge, response):
    """
        Stop responding for a particular challenge.

        May be a noop if a particular responder does not need or implement
        explicit cleanup; implementations should not rely on this method always
        being called.

        :param str server_name: The server name for which the challenge is
            being completed.
        :param challenge: The `acme.challenges` challenge object; the exact
            type of this object depends on the challenge type.
        :param response: The `acme.challenges` response object; the exact type
            of this object depends on the challenge type.
        """
