On Python 3.8, there's a difference between how datetime.datetime.strftime renders %Y for years < 1000 between Linux and other platforms.

# Linux
$ docker run -it python python -c 'import datetime; print(datetime.date(900,1,1).strftime("%Y"))'                       
900

# macOS
$ python -c 'import datetime; print(datetime.date(900,1,1).strftime("%Y"))'                                             
0900


According to the docs (https://docs.python.org/3/library/datetime.html#strftime-strptime-behavior), one should expect `'0000'` for year zero and so I'd expect `'0900'` for the year 900, so the macOS behavior looks correct to me.