[Python-Dev] PEP 218 (sets); moving set.py to Lib

[Guido van Rossum]

> Hmm ... is there a case that NotImplementedError should be a
> subclass of TypeError? Conceptually it would make sense (this *type*
> does not implement this method).

I think you're overthinking this.  NotImplementedError is fine for
code that wants to send that particular message to the user.  We're
playing with TypeError here because we're trying to be close to the
metal.

--Guido van Rossum (home page: http://www.python.org/~guido/)