def _del_all_subscriptions(self, session):
        """
        Delete all topic subscriptions for a given session
        :param session:
        :return:
        """
        filter_queue = deque()
        for topic in self._subscriptions:
            if self._del_subscription(topic, session):
                filter_queue.append(topic)
        for topic in filter_queue:
            if not self._subscriptions[topic]:
                del self._subscriptions[topic]
Delete all topic subscriptions for a given session
        :param session:
        :return: