[Python-Dev] Semantic of isinstance

[Phillip J. Eby]

At 12:02 PM 6/28/2006 +1200, Greg Ewing wrote:
>Martin v. Löwis wrote:
>
> > Again, I believe this is all included for ExtensionClasses: it looks
> > for __class__ on the object if the type check fails, so that an
> > ExtensionClass could be actually a class derived from the C type.
>
>Now that we have had new-style classes for quite a
>while, is there still a need to support ExtensionClasses?

That's the wrong question.  The right question is, "is there a need to 
support isinstance() for proxy objects?" and the answer is yes.

As far as I know, nobody has proposed to change this behavior of 
isinstance(), nor even suggested a reason for doing so.