def _assert_no_hosts(self, action):
        if self.obj_what_changed() in 'hosts':
            raise exception.ObjectActionError(
                action=action,
                reason='hosts updated inline')
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/objects/aggregate.py/Aggregate._assert_no_hosts/swapped operands of `in`