This is now merged, thanks for the debate and opinions offered everyone, and thanks to Dong-hee for the implementation!

The way we did the implementation, a pickle/unpickle cycle on the result of .isocalendar() will return a plain tuple. Despite the fact that I suggested it, I recognize that this is a /weird thing to do/, and I'm sorta banking on the fact that in all likelihood no one is relying on pickling and unpickling the result of .isocalendar() returning anything but a tuple (since, currently, that's already what it does, regardless of what the input type was).

I suppose we'll have to see if it causes problems in the beta period, and I'll keep a close eye on it.