from abc import ABCMeta
class test1(object):
    __metaclass__ = ABCMeta 
    def test1(self):
        print 'test1'
    
class UpperAttrMetaclass(type):
    def __new__(cls, name, bases, dct={}):
        a = super(UpperAttrMetaclass, cls).__new__(cls, name, bases, dct)
        return a
    
b = UpperAttrMetaclass('hehe',(test1,),{})()

会报错如下：TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases

如果将test1中的__metaclass__ = ABCMeta去掉就能运行。但是不想去掉，如何在以上基础上解决呢？（程序是在运行时动态决定继承哪些类，继承的类名和数量都不一定）