private NodeR NextNodeR(NodeR currentNode)
        {
            var index         = _nodes.IndexOf(currentNode);
            var nextNodeIndex = index + 1;

            if (nextNodeIndex < _nodes.Count())
            {
                return(_nodes[nextNodeIndex]);
            }

            return(null);
        }
 private bool HasNextNodeR(NodeR currentNode) => NextNodeR(currentNode) != null;