@Override
	public short getLast() {
		if (root == null) {
			return -1;
		}
		RBNode node = root;

		while (node.right != null) {
			node = node.right;
		}
		return node.key;

	}
Returns the last key in this set.
Ghidra/Framework/Generic/src/main/java/ghidra/util/datastruct/RedBlackKeySet.java