public async Task <IEXResponse <IEnumerable <HolidaysAndTradingDatesUSResponse> > > HolidaysAndTradingDatesUSAsync( DateType type, DirectionType direction = DirectionType.Next, int last = 1, DateTime?startDate = null) { const string urlPattern = "ref-data/us/dates/[type]/[direction]/[last]/[startDate]"; var qsb = new QueryStringBuilder(); var pathNvc = new NameValueCollection { { "type", type.GetDescriptionFromEnum() }, { "direction", direction.GetDescriptionFromEnum() }, { "last", last.ToString() }, { "startDate", startDate == null?DateTime.Now.ToString("yyyyMMdd") : ((DateTime)startDate).ToString("yyyyMMdd") } }; return(await executor.ExecuteAsync <IEnumerable <HolidaysAndTradingDatesUSResponse> >(urlPattern, pathNvc, qsb)); }