小编Gra*_* F.的帖子

扩展抽象基类和从"对象"派生的类可以正常工作:如果您尚未实现所有抽象方法和属性,则会出现错误.

奇怪的是,用扩展"Exception"的类替换对象派生类允许您创建不实现所有必需的抽象方法和属性的类的实例.

例如:

import abc

# The superclasses
class myABC( object ):
    __metaclass__ = abc.ABCMeta

    @abc.abstractproperty
    def foo(self):
        pass

class myCustomException( Exception ):
    pass

class myObjectDerivedClass( object ):
    pass

# Mix them in different ways
class myConcreteClass_1(myCustomException, myABC):
    pass

class myConcreteClass_2(myObjectDerivedClass, myABC):
    pass

# Get surprising results
if __name__=='__main__':
    a = myConcreteClass_1()
    print "First instantiation done. We shouldn't get this far, but we do."
    b = myConcreteClass_2()
    print "Second instantiation done. We never reach here, which is good."

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