datetime.timedelta internally uses a triple of (days,seconds,microseconds) to represent it's data and exposes that to users of the class. That a timedelta can

datetime.timedelta internally uses a triple of (days,seconds,microseconds) to represent it's data and exposes that to users of the class. That a timedelta can be represented in multiple ways is alone quite surprising but some of the representations that happen can be very confusing. I think the example I gave which represents "-1 day and a few microseconds" as "-2 days + 86399 milliseconds + 999969 microseconds" is very surprising and it commonly happens in practice. For comparison, here's what postgres does: postgres=> select now() - (now() + '12 milliseconds'::interval + '1 day'::interval); ?column? ----------------------- -1 days -00:00:00.012 (1 row)