When using RedisExpireStorage you get the exception: `redis.exceptions.DataError: Invalid input of type: 'function'. Convert to a bytes, string, int or float first.

[sluce23andme]

Basically huey.storage.RedisExpireStorage uses a lambda to define self.result_key instead of being a simple string:

class RedisExpireStorage(RedisStorage):
    # Redis storage subclass that adds expiration to task result values. Since
    # the Redis server handles deleting our results after the expiration time,
    # this storage layer will not delete the results when they are read.
    def __init__(self, name='huey', expire_time=86400, *args, **kwargs):
        super(RedisExpireStorage, self).__init__(name, *args, **kwargs)

        self._expire_time = expire_time

        self.result_prefix = rp = b'huey.r.%s.' % self.name.encode('utf8')
        encode = lambda s: s if isinstance(s, bytes) else s.encode('utf8')
        self.result_key = lambda k: rp + encode(k)

I have not looked into this any deeper at this point and have switched to PriorityRedisStorage for now.