def test_lookup(self):
        assert event.Priority.lookup(event.Priority.CORE) is event.Priority.CORE
        assert event.Priority.lookup(event.Priority.CORE.value) is event.Priority.CORE
        assert event.Priority.lookup(-12312412) == -12312412
def remove(root, key):
    left, right = split(root, key)
    return merge(left, split(right, key + 1)[1])