code: function mxGraphHierarchyEdge(edges)
  {
  	mxGraphAbstractHierarchyCell.apply(this, arguments);
  	this.edges = edges;
  	this.ids = [];
  	
  	for (var i = 0; i < edges.length; i++)
  	{
  		this.ids.push(mxObjectIdentity.get(edges[i]));
  	}
  }
docs: Copyright (c) 2006-2015, JGraph Ltd
  Copyright (c) 2006-2015, Gaudenz Alder
   
  Class: mxGraphHierarchyEdge
  
  An abstraction of a hierarchical edge for the hierarchy layout
  
  Constructor: mxGraphHierarchyEdge
  
  Constructs a hierarchy edge
  
  Arguments:
  
  edges - a list of real graph edges this abstraction represents