Hello, consider this code
>>> class A(object): ... def __init__(self): ... self.a = 1 ... self.b = 2 ... >>> class B(A): ... __slots__ = ["x","y"] ... >>> b=B() >>> b.a 1 >>> b.b 2 >>> b.x = 100 >>> b.y = 100 >>> b.z = 100 no exception here does __slots__ nothing when used in derived classes? >>> >>> >>> class Z(object): ... __slots__ = ["x","y"] ... >>> z=Z() >>> z.x = 100 >>> z.y = 100 >>> z.z = 100 Traceback (most recent call last): File "<stdin>", line 1, in ? AttributeError: 'Z' object has no attribute 'z' >>> here it works like expected Regards, Daniel -- http://mail.python.org/mailman/listinfo/python-list