code: function(eventType, activityId) {
        var attrsKey = this._event_attributes_key(eventType);
        return this._events.some(function (evt) {
            if (evt.eventType === eventType) {
               if (this.activityIdFor(evt[attrsKey].scheduledEventId) === activityId) {
                  return true;
               }
            }
         }, this);
     }
docs: Search for an event with the corresponding type that matches the scheduled activityId
  @param {String} eventType
  @param {String} activityId
  @returns {Boolean}