code: function(opacity, animate) {
          var me = this;
  
          if (!me.dom) {
              return me;
          }
  
          if (!animate || !me.anim) {
              me.setStyle('opacity', opacity);
          }
          else {
              if (typeof animate != 'object') {
                  animate = {
                      duration: 350,
                      easing: 'ease-in'
                  };
              }
  
              me.animate(Ext.applyIf({
                  to: {
                      opacity: opacity
                  }
              }, animate));
          }
          return me;
      }
docs: Set the opacity of the element
  @param {Number} opacity The new opacity. 0 = transparent, .5 = 50% visibile, 1 = fully visible, etc
  @param {Boolean/Object} [animate] a standard Element animation config object or `true` for
  the default animation (`{duration: 350, easing: 'easeIn'}`)
  @return {Ext.dom.Element} this