Thomas (HFM) Wyant wrote: >It seems to me that in at least some such cases subclassing >DateTime would be a better alternative.
You've run into the terrible factoring of the DateTime system. All three of the modules you named already suffer from it, but subclassing DateTime would make things worse. For subclassing to be the right answer, the objects of your classes would have to be everything that DateTime objects are, plus something that you're adding. But one of the things that DateTime objects are is Gregorian, which your objects are not. -zefram
