WHUI! (was Re: [Python-Dev] Proposal: C API Macro to decref and set to NULL)

[Tim Peters]

[Jim]
> The documentation is still off I think, as it says that a
> non-zero value indicates an error, but I don't think that this
> is true.

I checked in doc chages, to clarify this, and to clarify that a NULL
cannot be passed as the first arg to the visit() callback, and to
clarify that users aren't normally expected to write visit() callbacks
themselves (they're supplied by the core).