[Python-3000] Builtin iterator type

[Bill Janssen]

> Java interfaces are very useful, however. Java programming seems to be 
> less and less about inheritance and more and more about implementing 
> interfaces; at least it does amongst Java programmers with taste :-)

It seems to me that that's where Python has a real advantage.  With
real support for multiple inheritance, Python "interfaces" could be
real classes (either like real Java classes or Java abstract classes),
perhaps providing default implementations.  You get the goodness of
mix-ins, along with interface communication.

Bill