> The patch as-is can't be accepted if not for Python 4.x maybe,
> obviously because it's just too breaking.

With all due respect, this sounds a bit silly. If the attributes were of the "__private" kind, they weren't meant to be used by other classes, and so there's no problem in making them public. (the reverse would be more annoying)

However, making them public means they should be maintained with the same semantics in future versions, which might be too much of a burden. In this case, perhaps you want to make them of the "_private" kind instead.