如何在python队列中实现多线程？

import threading
import time
import queue
def work(q):
    while True:
        if q.empty():
            return
        else:
            t = q.get()
            print("当前线程sleep {} 秒".format(t))
            time.sleep(t)
def main():
    q = queue.Queue()
    for i in range(5):
        q.put(i)  
thread_num = 5
    threads = []
    for i in range(thread_num):
        t = threading.Thread(target=work, args=(q,))