test025.py

class MyMeta(type):
    def __new__(cls, name, bases, dct):
        print "meta: creating %s %s" % (name, bases)
        for pkls in bases:
            for key, value in pkls.__dict__.items():
                if isinstance(value, Field):
                    pass
                    #print name,value
                    #setattr(kls, key, value)
        kls = type.__new__(cls, name, bases, dct)
        return kls

    def meta_meth(cls):
        print "MyMeta.meta_meth"

    __repr__ = lambda c: c.__name__

class Field(object):
    def __init__(self, field):
        self.field = field

    def __set__(self, instance, val):
        setattr(instance, self.field, val)

    def __get__(self, instance, cls):
        if instance:
            return getattr(instance, self.field, None)
        return self



class A(object):
    __metaclass__ = MyMeta
    name = Field('_name')
    age = Field('_age')
    address = None
    def __init__(self):
        super(A, self).__init__()
        print "A init"

    def meth(self):
        print "A.meth"

class B(object):
    __metaclass__ = MyMeta
    def __init__(self):
        super(B, self).__init__()
        print "B init"

    def meth(self):
        print "B.meth"

class C(A, B):
    __metaclass__ = MyMeta
    def __init__(self):
        super(C, self).__init__()
        print "C init"
print A.name
print C.name

test046.py

"""
write __metaclass__ in class directly.
"""
class ActiveRecord(object):

    class __metaclass__(type):
        def __new__(meta_cls, meta_cls_name, bases, dct):
            print('__metaclass__ __new__', meta_cls, meta_cls_name, bases, dct)
            return type.__new__(meta_cls, meta_cls_name, bases, dct)

        def __init__(cls, name, bases, dct):
            print('__metaclass__ __init__', cls, name)



class Foo(ActiveRecord):
    pass

if __name__ == '__main__':
    print('go')