def test_iter(self):
        prio_set_list = event._PrioritizedSetList()
        objs = [(i,) for i in range(5)]
        for i, obj in enumerate(objs):
            prio_set_list.add(-i, obj)

        for i, set_ in enumerate(prio_set_list):
            assert set_ == (-i, {objs[i]})
def kth(root, k):
    if k < size(root.left):
        return kth(root.left, k)
    elif k > size(root.left):
        return kth(root.right, k - size(root.left) - 1)
    return root.key