

I don’t think this is implemented in the standard datetime library, but in principle overriding sub is easily possible and you can define it as you’d wish.
However, I think subtracting a year is a bit ill defined, because it isn’t clear which year you’re subtracting given the leap year issue.









separate drive with rEFInd as boot manager is fine. Windows will sometimes still alter the boot sequence to make it take priority, but that’s a relatively quick fix and doesn’t happen all that often.