public static void RemoveEdge(this Vertex v, Edge e)
{
if (v.fromEdges.Contains(e)) {
Undo.RecordObject(v, "Remove From Edge");
v.fromEdges.Remove(e);
}
}
public static void AddEdge(this Vertex v, Edge e)
{
if (! v.fromEdges.Contains(e)) {
Undo.RecordObject(v, "Add From Edge");
v.fromEdges.Add(e);
}
}