[docs] [issue33082] multiprocessing docs bury very important 'callback=' args

Ned Deily <nad@python.org> added the comment: These doc changes have been languishing. We have a difference of opinion about adding a callback example. I don't have a strong feeling one way or the other. Davin or anyone else, what say you? ---------- nosy: +ned.deily _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33082> _______________________________________