code: function(opts) {
          var tag = opts.tag,
              targetID = opts.target.id
  
          var element = this.targets[targetID]
          if (!element) {
              return null
          }
          for (var i = 0; i < element.actions.length; i++ ) {
              if (element.actions[i] &&
                  (element.actions[i].tag === tag)) {
                  return element.actions[i]
              }
          }
          // Not found
          return null
      }
docs: Fetch an action belonging to a cocos.nodes.Node
  
  @returns {cocos.actions.Action}
  
  @opts {cocos.nodes.Node} target Target of the action
  @opts {String} tag Tag of the action