public IEdge CreateEdge(
INode sourceNode,
INode endNode,
IAttributeDictionary attrs = null,
IPort sourcePort = null,
IPort endPort = null)
{
var edge = new Edge(this, sourceNode, endNode, sourcePort, endPort);
var addedEdge = Root.AddEdge(edge);
addedEdge.SetAttributes(attrs);
return(addedEdge);
}