[Python-Dev] 'hasattr' is broken by design

[P.J. Eby]

At 03:37 PM 8/24/2010 +0200, Hrvoje Niksic wrote:
>a) a "business" case of throwing anything other than AttributeError 
>from __getattr__ and friends is almost certainly a bug waiting to happen, and

FYI, best practice for __getattr__ is generally to bail with an 
AttributeError as soon as you see double underscores in the name, 
unless you intend to support special attributes.

I don't think this is documented anywhere, but experience got this 
pretty ingrained in my head since Python 2.2 or even earlier.