mxGraph.prototype.validateCell=function(a,b){return null};mxGraph.prototype.getBackgroundImage=function(){return this.backgroundImage};mxGraph.prototype.setBackgroundImage=function(a){this.backgroundImage=a};mxGraph.prototype.getFoldingImage=function(a){if(null!=a&&this.foldingEnabled&&!this.getModel().isEdge(a.cell)){var b=this.isCellCollapsed(a.cell);if(this.isCellFoldable(a.cell,!b))return b?this.collapsedImage:this.expandedImage}return null};