code: function (options) {
          var maxExtent = null;
          if(options && options.restricted && this.restrictedExtent){
              maxExtent = this.restrictedExtent;
          } else if (this.baseLayer != null) {
              maxExtent = this.baseLayer.maxExtent;
          }        
          return maxExtent;
      }
docs: APIMethod: getMaxExtent
  
  Parameters:
  options - {Object}
  
  Allowed Options:
  restricted - {Boolean} If true, returns restricted extent (if it is
  available.)
  
  Returns:
  {<OpenLayers.Bounds>} The maxExtent property as set on the current
  baselayer, unless the 'restricted' option is set, in which case
  the 'restrictedExtent' option from the map is returned (if it
  is set).