python 清理没有过期时间的redis

import redis
import time
import asyncio
import sys


async def set_expire_do(i):
    pool = redis.ConnectionPool(host="host", password="pwd",
                                port=6379, db=i)
    r = redis.StrictRedis(connection_pool=pool)
    count = 0
    for key in r.scan_iter():
        _time = r.ttl(key)
　　　　　# 没有过期时间
        if _time == -1:
            count += 1
            r.expire(key, 1000)
            if count % 1000 == 0:
                print('已处理：', count, '条')
        else:
            continue
    print('redis库:', i, "no expire keys  {0}".format(count))


async def main():
    start = time.time()
    dbs = sys.argv[1:]
    if dbs:
        for db in dbs:
            await set_expire_do(db)
    else:
        for db in range(10):
            await set_expire_do(db)
    end = time.time()
    print("耗时： {0} 秒".format(end - start))

loop = asyncio.get_event_loop()
loop.run_until_complete(main())
loop.close()