问如何从dramatiq python中获取处理结果？

EN

import dramatiq
from dramatiq.brokers.redis import RedisBroker
from dramatiq.results import Results
from dramatiq.results.backends import RedisBackend

broker = RedisBroker(host="127.0.0.1", port=6379)
broker.declare_queue("default")
dramatiq.set_broker(broker)
# backend = RedisBackend()
# broker.add_middleware(Results(backend=backend))

@dramatiq.actor()
def print_words(text):
        print('This is ' + text)

print_words('sync')
a = print_words.send('async')
a.get_results()