大神指导下...什么意思啊

菜鸟在学datetime时候看方法发现...不知道什么意思，求大神指点
def __init__(self, year: int, month: int, day: int, hour: int = ...,
             minute: int = ..., second: int = ..., microsecond: int = ...,
             tzinfo: Optional[tzinfo] = ...) -> None: ...