I don't like the idea of importing from redis-py library.
If they ever alter the name of this method or its argument list we'll get errors in code relying on tornado-redis.

I think it's a great idea to re-use mainstream, mature and well-maintained code, but we need to be able to update tornado-redis code in hours after redis-py code update. I can not guarantee this.

You may copy the `parse_sentinel` method's code to tornado-redis project. I need to mention that although the whole tornado-redis project is based on redis-py code base, I don't know if we ever asked permission to use it, because I forked brukva project when started tornado-redis and it already had code very similar to redis-py. So maybe you'd like to ask the permission from redis-py authors to use their code in our project before copying it.