Same AttributeError message in some getter function

[shenxiangzhuang]

I see many getter methods raise same AttributeError as fellow(code):

@property
def extremes_method(self) -> typing.Literal["BM", "POT"]:
    if self.__extremes_method is None:
        raise AttributeError(
            "extreme values must first be extracted "
            "using the '.get_extremes' method"
        )
    return self.__extremes_method

All of them with same error message "extreme values must first be extracted using the '.get_extremes' method". Does this behavior is designed by some purpose or just a wrong copy :-)

[georgebv]

The idea is that those attributes should not exist until user calls get_extremes. I had a choice between returning None and throwing an exception. Message is indeed the same - could be refactored to use global variable.