docs: function (evt, callback) {
      var self = this;
  
      var extendedEvent = evt;
  
      this.extendEventHandle(evt, function (err, extEvt) {
        if (err) {
          debug(err);
        }
  
        extendedEvent = extEvt || extendedEvent;
  
        var eventExtender = self.tree.getEventExtender(self.eventDispatcher.getTargetInformation(evt));
  
        if (!eventExtender) {
          return callback(err, extendedEvent);
        }
  
        eventExtender.extend(extendedEvent, function (err, extEvt) {
          if (err) {
            debug(err);
          }
          extendedEvent = extEvt || extendedEvent;
          callback(err, extendedEvent);
        });
  
      });
    }