code: function (o,evt) {
          var ce,i,len,j,subs,newSubs;
  
          if (o.__yui_events && o.events[evt]) {
              for (i = o.__yui_events.length; i >= 0; --i) {
                  if (o.__yui_events[i].type === evt) {
                      ce = o.__yui_events[i];
                      break;
                  }
              }
              if (ce) {
                  subs    = ce.subscribers;
                  newSubs = [];
                  j = 0;
                  for (i = 0, len = subs.length; i < len; ++i) {
                      if (subs[i]) {
                          newSubs[j++] = subs[i];
                      }
                  }
                  ce.subscribers = newSubs;
              }
          }
      }
docs: Clean up the slideEnd event subscribers array, since each one-time
  callback will be replaced in the event's subscribers property with
  null.  This will cause memory bloat and loss of performance.
  @method _cleanEvent
  @param o {EventProvider} object housing the CustomEvent
  @param evt {string} name of the CustomEvent
  @private