[Python-Dev] Metatype conflict among bases?

[David Abrahams]

Consider:

    class A(object):
        class __metaclass__(type):
            pass

    class B(A):  # TypeError: metatype conflict among bases
        class __metaclass__(type):
            pass

Now that's a weird error message at least!  There's only one base (A),
and I'm telling Python explicitly to use the nested __metaclass__
instead of A's __metaclass__!

Should I not be surprised that Python won't let me set the metatype
explicitly?

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com