code: function(triggers, mode, fn) {
              var t, tce;
  
              for (var i = 0, l = triggers.length; i < l; ++i) {
                  t = triggers[i];
                  tce = this._findTriggerCE(t);
                  if (tce) {
                      tce[mode](fn, this, true);
                  } else {
                      this[mode](t, fn);
                  }
              }
          }
docs: Utility method that subscribes or unsubscribes the given
  function from the list of trigger events provided.
  
  @method _processTriggers
  @protected
  
  @param {Array[String|CustomEvent]} triggers An array of either CustomEvents, event type strings
  (e.g. "beforeShow", "windowScroll") to/from which the provided function should be
  subscribed/unsubscribed respectively.
  
  @param {String} mode Either "subscribe" or "unsubscribe", specifying whether or not
  we are subscribing or unsubscribing trigger listeners
  
  @param {Function} fn The function to be subscribed/unsubscribed to/from the trigger event.
  Context is always set to the overlay instance, and no additional object argument
  get passed to the subscribed function.