private void InsertBreakBetween(string stationA, string stationB)
        {
            int aId = sd.GetKey(stationA);
            int bId = sd.GetKey(stationB);

            if (aId == -1)
            {
                throw new ArgumentException(stationA + " is misspelt");
            }

            if (bId == -1)
            {
                throw new ArgumentException(stationB + " is misspelt");
            }

            var children = MetroNetwork.GenChildrenFromStationId(aId);

            for (int i = 0; i < children.Count(); i++)
            {
                if (children[i].StationId == bId)
                {
                    MetroNetwork.InsertBreakBetween(aId, children[i]);
                    break;
                }
            }
        }
        public string CutEdge(int index)
        {
            Node child = Children[index];

            MetroNetwork.InsertBreakBetween(ParentId, child);

            string rec = LineDiction.GetValue(child.LineIndex) + ": " + StationDiction.GetValue(ParentId) + " - " + StationDiction.GetValue(child.StationId);

            return(rec);
        }