Stylistic question about inheritance

[Andrew Koenig]

"Carl Banks" <invalidemail at aerojockey.com> wrote in message 
news:1112300127.449931.146470 at o13g2000cwo.googlegroups.com...

> Well, Python seems to get along fine without the ability to do
> isinstance(foo,file_like_object); probably better off in the end for
> it.  So I'd say you should generally not do it.  Inheritence is for
> when different classes need to share functionality.

That's really the question:  Is it for when they need to share 
functionality, or when they are conceptually related in ways that might lead 
to shared functionality later?