docs: function(applicationId, start, end) {
      return new Promise((resolve, reject) => {
        this._start()
            .uri('/api/report/daily-active-user')
            .urlParameter('applicationId', applicationId)
            .urlParameter('start', start)
            .urlParameter('end', end)
            .get()
            .go(this._responseHandler(resolve, reject));
      });
    }