code: function (obj) { 
          if (obj == null) { 
              obj = new OpenLayers.Layer.ArcGISCache(this.name, this.url, this.options);
          }
          return OpenLayers.Layer.XYZ.prototype.clone.apply(this, [obj]);
      }
docs: APIMethod: clone
  Returns an exact clone of this OpenLayers.Layer.ArcGISCache
  
  Parameters:
  [obj] - {Object} optional object to assign the cloned instance to.
  
  Returns:
  {<OpenLayers.Layer.ArcGISCache>} clone of this instance