NCrontab.Advanced.CrontabSchedule.CheckForIllegalFilters C# (CSharp) Method

        public static void CheckForIllegalFilters(Dictionary<CrontabFieldKind, List<ICronFilter>> filters)
        {
            var monthSingle = GetSpecificFilters(filters, CrontabFieldKind.Month);
            var daySingle = GetSpecificFilters(filters, CrontabFieldKind.Day);

            if (monthSingle.Any() && monthSingle.All(x => x.SpecificValue == 2))
            {
                if (daySingle.Any() && daySingle.All(x => (x.SpecificValue == 30) || (x.SpecificValue == 31)))
                    throw new CrontabException("Nice try, but February 30 and 31 don't exist.");
            }
        }