[Python-3000] Builtin iterator type

[Greg Ewing]

Andrew Koenig wrote:

> That's a nice general sentiment, but not always feasible -- especially if
> you're writing library code.

I've written a fair bit of library code, and I've never
found a pressing need to test for an abstract interface.

In the rare cases where I've used type testing in an
API, it's always been for specific well-known concrete
types, such as strings and tuples -- never anything so
abstract as "iterator", "sequence", etc.

--
Greg