如何在python中把时间值（字符串）转换为datetime？

所以，我一直在试图工作在一个语句，我应该从用户的时间值，如果它是在一定的时间值之间，我应该问候用户早上好！，中午后好，晚上好，晚安。用户将以HH:MM:SS的格式输入时间，我的函数代码看起来像这样。

r = datetime.time(12, 00, 00)
t = datetime.time(18, 00, 00)
u = datetime.time(6, 00, 00)
p = datetime.time(23, 59, 00)
def my_function:
time=input('what is the time?')
    if datetime.datetime.strptime(time, '%H:%M:%S')>=u and datetime.datetime.strptime(time, '%H:%M:%S')<r:
        print('Morning')
    elif datetime.datetime.strptime(time, '%H:%M:%S')>=r and datetime.datetime.strptime(time, '%H:%M:%S')<t:
        print('Afternoon')
    elif datetime.datetime.strptime(time, '%H:%M:%S')>=t and datetime.datetime.strptime(time, '%H:%M:%S')<p:
        print('Evening')
    elif datetime.datetime.strptime(time, '%H:%M:%S')>=p and datetime.datetime.strptime(time, '%H:%M:%S')<u:
        print('Night')
    else:
        return 'invalid'

当我尝试调用该函数时，我返回了错误的时间数据 “what is the time?” does not match format ‘%H:%M:%S’. 谁能给点建议，如何修改我的代码，或者说我做错了什么？ 非常感谢

edit:在’datetime.datetime’和’datetime.time’实例之间出现了’>=’不支持的错误。

解决方案：

def my_function():

    r = datetime.time(12, 00, 00)
    t = datetime.time(18, 00, 00)
    u = datetime.time(6, 00, 00)
    p = datetime.time(23, 59, 00)

    time = input('what is the time?')
    time = datetime.datetime.strptime(time, '%H:%M:%S').time()

    if u <= time < r:
        return('Morning')
    elif r <= time < t:
        return('Afternoon')
    elif t <= time < p:
        return('Evening')
    elif p <= time or time < u:
        return('Night')
    else:
        return 'invalid'

 print(my_function())