Meador Inge <report@bugs.python.org> wrote:
> The behavior around '__int__' in previous versions seems somewhat accidental.

I think struct followed the functions in longobject.c, which is not
really consistent with respect to duck typing. See also #12965 or
http://bugs.python.org/issue1172711#msg48086.

But I think that the decision to accept __index__() for both signed
and unsigned integer formats is good for consistency.

For 'P' I'm not sure, but course it might be used in the wild by now.