private IScheduleBuilder CreateScheduleWithAmountAndIntervalUnit(string amountString, string intervalUnitString, TimeZoneInfo timeZone)
        {
            var intervalUnit = GrammarHelper.GetIntervalUnitValueFromString(intervalUnitString);

            int amount = 1;

            if (amountString != null)
            {
                amount = GrammarHelper.GetAmountValueFromString(amountString);
            }

            CalendarIntervalScheduleBuilder b = CalendarIntervalScheduleBuilder.Create();

            b.WithInterval(amount, intervalUnit);

            b.PreserveHourOfDayAcrossDaylightSavings(true);
            b.SkipDayIfHourDoesNotExist(false);
            b.InTimeZone(timeZone);
            return(b);
        }