docs: 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]));
  	}
  }