_UrlopenRet is defined _UrlopenRet = Union[_HTTPResponse, addinfourl] but addinfourl has to attribute status so when checking the status of an HTTPResponse you receive error: Item "addinfourl" of "Union[HTTPResponse, addinfourl]" has no attribute "status"

https://github.com/python/cpython/blob/3.7/Lib/urllib/response.py#L68-L80