mxGraphModel.prototype.getParent=function(a){return null!=a?a.getParent():null};mxGraphModel.prototype.add=function(a,b,c){if(b!=a&&null!=a&&null!=b){null==c&&(c=this.getChildCount(a));var d=a!=this.getParent(b);this.execute(new mxChildChange(this,a,b,c));this.maintainEdgeParent&&d&&this.updateEdgeParents(b)}return b};