How to close a subscription and return it back to a pool with asyncio_redis

close_subscription.py

class MessageIterator:
    '''
    Async iterator for messages received.
    Only necessary as a separate class since async generators won't be introduced until 3.6
    '''
    def __init__(self, redis_conn, channel_name):
        self.redis_conn = redis_conn  # redis_conn can also be a pool, they have the same api
        self.channel_name = channel_name
        self.subscriber = None

    def __aiter__(self):
        return self

    async def __anext__(self):
        if self.subscriber is None:
            self.subscriber = await self.redis_conn.start_subscribe()
            await self.subscriber.subscribe([self.channel_name])

        message = await self.subscriber.next_message()
        return message

    async def close(self):
        await self.subscriber.unsubscribe([self.channel_name])

        # Now for some hackish stuff so we can reuse the connection later
        conn = self.subscriber.protocol
        assert not conn._pubsub_channels and not conn._pubsub_patterns, 'Cannot exit pubsub mode while subscribed to 1 or more channels'
        conn._in_pubsub = False
        conn._subscription = None