[Python-3000] Bug 3139

["Martin v. Löwis"]

> I think it's definitely too short. Martin has outlined a clean solution to this
> but it's a lot of changes. Let's wait for beta 3.

FWIW, I started writing code today. I couldn't complete it, either (i.e.
it's for 2.6 only, has no docs, and only fixes a single function), but I
hope to submit a patch next week (if not, I'll provide a snapshot of my
patch).