how to find out if an object is a class?

[Terry Reedy]

Wojtek Walczak wrote:
> Dnia Thu, 7 Aug 2008 14:36:37 -0700 (PDT), szczepiq napisa�(a):
>> Pardon me for most likely a dummy question but how do I find out if an
>> object is a class?
> 
> 
> Use types.ClassType:
> 
>>>> class Q:
> ...    pass
> ...
>>>> import types
>>>> isinstance(Q, types.ClassType)
>>>> True

That is only true and only works for 2.x old-style classes and not for 
2.x new-style classes and all 3.0 classes, for which isinstance(Q,type) 
is True.

 >>> class old: pass
...
 >>> type(old)
<type 'classobj'>
 >>> class new(object): pass
...
 >>> type(new)
<type 'type'>