@classmethod
def to_result_topic(cls, invocation_topic):
    """Takes an Action invocation MQTT topic and returns the related result topic."""
    topic_split = invocation_topic.split('/')
    servient_id, thing_name, action_name = topic_split[-5], topic_split[-2
        ], topic_split[-1]
    return '{}/action/result/{}/{}'.format(servient_id, thing_name, action_name
        )
