Most reliable/pythonic way to tell if an instance comes from a class implemented in C/etc?

[Duncan Booth]

Terry Reedy <tjreedy at udel.edu> wrote:

> Builtin classes, named or not, do not have dotted names
> 
> >>> 1 .__class__
><class 'int'>
> >>> class C: pass
> 
> I believe all others do, including C-coded extension classes.
> 
> >>> C().__class__
><class '__main__.C'>
> 

Not quite all. Classes created by calling the type constructor directly 
don't have to follow that rule:

>>> C = type('Fred', (object,), {})
>>> C.__name__
'Fred'