/// <summary>
 /// Walks the edge supplied and returns the node at the end. As out the data on the edge is returned
 /// </summary>
 /// <param name="edgeKey"></param>
 /// <param name="edgeData"></param>
 /// <returns></returns>
 public Node WalkEdge(string edgeKey, out EdgeData edgeData)
 {
     if (NextEdges.TryGetValue(edgeKey, out Edge edge))
     {
         edgeData = edge.EdgeData;
         return(edge.ToNode);
     }
     else
     {
         throw new DoubleLinkedDirectedGraphException($"Cannot walk edge {edgeKey} because it does not exist");
     }
 }
            /// <summary>
            /// Walks the edge supplied and returns the node at the end.
            /// </summary>
            /// <param name="nextNodeKey"></param>
            /// <returns></returns>
            public Node WalkEdge(string nextNodeKey)
            {
                string edgeKey = CreateEdgeKey(NodeKey, nextNodeKey);

                if (NextEdges.TryGetValue(edgeKey, out Edge edge))
                {
                    return(edge.ToNode);
                }
                else
                {
                    throw new DoubleLinkedDirectedGraphException($"Cannot walk edge {edgeKey} because it does not exist");
                }
            }