[Python] Is it possible to limit attributes in a Python sub class using __slots__?

One use of __slots__ in Python is to disallow new attributes:

class Thing:
__slots__ = 'a', 'b'

thing = Thing()
thing.c = 'hello' # error


However, this doesn’t work if a class inherits from another slotless class:

class Whatever:
pass

class Thing(Whatever):
__slots__ = 'a', 'b'

thing = Thing()
thing.c = 'hello' # ok


That’s because it also inherits the __dict__ from its parent which allows additional attributes.

Is there any way of blocking the __dict__ from being inherited?

It seems to me that this would allow a sub class to be less generic that its parent, so it’s surprising that it doesn’t work this way naturally.

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