def set(self, obj, name, value):
        if self._vals not in obj:
            self._vals[obj] = {}
        old = self.get(obj, name)
        if value != old:
            self._vals[obj][name] = self._trait.validate(obj, name, value)
            obj.trait_property_changed(name, old, value)
dataset/ETHPy150Open OpenMDAO/OpenMDAO-Framework/openmdao.main/src/openmdao/main/assembly.py/PassthroughProperty.set/swapped operands of `not in`