bpo-28602: [WIP] Add fold support to fromutc #7425
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This is an example implementation of generic fold support in
datetime.fromutc, for purposes of discussion. The idea here is that so long asutcoffset - dstis constant (as is the fundamental assumption of the currentfromutcimplementation) and theutcoffsetanddstimplementations respect thefoldparameter, this will always set thefoldparameter correctly infromutc.This needs more extensive tests and a pure Python implementation (plus I don't think I was amazingly careful about the reference counts), but the overall outline is there. It's basically a port of the current base dateutil implementation.
See GH-72788.
https://bugs.python.org/issue28602