What would this give:

   tm = datetime.time(13, 20)
   later = tm + datetime.timedelta(hours=47, minutes=44)

datetime.time(13, 4)? Or raise an exception?

I've thought about this before, but it's always a problem when going over date boundaries. If you define "+" to be modulo 24 hours, then it's not very useful for cases I've looked at. Every time I've used time by itself, I end up going back to datetime. But I'll admit that might be a shortcoming of mine, not the concept.