python中多线程

import threading
import time
from datetime import datetime as dt


def say_hello(word):
    time.sleep(1)
    print(word)


pool = []
now = dt.now()
for x in range(10):
    t = threading.Thread(target=say_hello, args=(x,))
    t.start()
    pool.append(t)

for t in pool:
    t.join()
end = dt.now()
print('总时间:', (end - now).total_seconds())