def test_difference_update_with_no_arguments(self):
python_set = set([1, 2, 3])
python_set.difference_update()
ts = TraitSet([1, 2, 3])
ts.difference_update()
self.assertEqual(ts, python_set)
def test_difference_update_varargs(self):
ts = TraitSet([1, 2, 3], notifiers=[self.notification_handler])
ts.difference_update([2], [3])
self.assertEqual(self.removed, {2, 3})