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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def receive_empty(self, empty, transaction):
 """ Manage the observe feature to remove a client in case of a RST message receveide in reply to a notification. :type empty: Message :param empty: the received message :type transaction: Transaction :param transaction: the transaction that owns the notification message :rtype : Transaction :return: the modified transaction """

        if empty.type == defines.Types["RST"]:
            host, port = transaction.request.source
            key_token = hash(str(host) + str(port) + str(transaction.request.token))
            logger.info("Remove Subscriber")
            try:
                del self._relations[key_token]
            except KeyError:
                pass
            transaction.completed = True
        return transaction