What is a classmethod for?

[Terry Reedy]

"Dennis Peterson" <denpeterson at yahoo.com> wrote in message
news:addgv30f4d at enews4.newsguy.com...
> class C:
>     def foo(cls):
>         print cls
>     foo = classmethod(foo)
...
> That's nice, but I can't think of a use for it, given that we have
> inheritance and isinstance(). Can anyone enlighten me?

Suppose, more realistically, that .__init__() adds each instance to a
list of class instances.  Then a reasonable classmethod would be one
that does something with that class attribute.

TJR