autoattributeobject.py

class A1(object):
    def __init__(self, **kwargs):
        for k,v in kwargs.items():
            setattr(self, k, v)

class A2(object):
    def __init__(self, **kwargs):
        self.__dict__.update(kwargs)

class B1(A1):
    def __init__(self):
        super(B1, self).__init__(test=1)
    
    @property
    def test(self):
        return 42

class B2(A2):
    def __init__(self):
        super(B2, self).__init__(test=1)
    
    @property
    def test(self):
        return 42

test = B2()
print test.test  # outputs 42
test = B1()      # AttributeError: can't set attribute