def main():
    # 测试单线程
    # single_thread()
    # 输出：
    '''
    I am listening to music 0
    I am listening to music 1
    I am listening to music 2
    I am listening to music 3
    I am listening to music 4
    I am listening to music 5
    I am listening to music 6
    I am listening to music 7
    I am listening to music 8
    I am listening to music 9
    I am watching movie 0
    I am watching movie 1
    [finished function:single_thread in 20.14s]
    '''