第十一节 yield实现多任务

import time

def test1():
    while True:
        print('.....1......')
        time.sleep(0.2)
        yield


def test2():
    while True:
        print('......2......')
        time.sleep(0.2)
        yield


def main():
    t1 = test1()
    t2 = test2()
    while True:
        next(t1)
        next(t2)

if __name__ == '__main__':
    main()