public static DateStamp AddMarketDays(this IInstrument instrument, DateStamp date, int numMarketDays) { if (numMarketDays == 0) { return(date); } for (var i = 1; i <= numMarketDays; i++) { do { date = date.AddDays(1); } while (!instrument.IsMarketDay(date)); } for (var i = -1; i >= numMarketDays; i--) { do { date = date.AddDays(-1); } while (!instrument.IsMarketDay(date)); } return(date); }