Re: [Python-Dev] draft pep: backwards compatibility

Benjamin Peterson <benjamin <at> python.org> writes:

I mean that if you pass X and Y into a function and get Z in 2.6, then you should be able to get Z from passing X and Y in 2.7 even if there's a new argument that returns Z' if you pass True to it.

Well, except if returning Z rather than Z' was a bug. Regards Antoine.