System.util.collections.OrderedTree.ContainsKey C# (CSharp) Method

        public bool ContainsKey(IComparable key)
        {
            OrderedTreeNode treeNode = rbTree; // begin at root
            int result = 0;
            // traverse tree until node is found
            while(treeNode != sentinelNode) {
                result = key.CompareTo(treeNode.Key);
                if(result == 0) {
                    lastNodeFound = treeNode;
                    return true;
                }
                if(result < 0)
                    treeNode = treeNode.Left;
                else
                    treeNode = treeNode.Right;
            }
            return false;
        }