code: function(obj) {
          var i = 0,
              items = this.items,
              surface = this.getSurface(),
              len = this.length;
          
          if (surface) {
              for (; i < len; i++) {
                  surface.addCls(items[i], obj);
              }
          }
      }
docs: Adds class to all sprites.
  @param {String} cls CSS class name