System.Globalization.GregorianCalendar.IsLeapDay C# (CSharp) Метод

        public override bool IsLeapDay(int year, int month, int day, int era)
        {
            if (era != CurrentEra && era != ADEra) {
                throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
            }
            if (year < 1 || year > MaxYear) {
                throw new ArgumentOutOfRangeException(
                                "year",
                                String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
            }

            if (month < 1 || month > 12) {
                throw new ArgumentOutOfRangeException("month", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"),
                    1, 12));
            }
            if (day < 1 || day > GetDaysInMonth(year, month)) {
                throw new ArgumentOutOfRangeException("day", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"),
                    1, GetDaysInMonth(year, month)));
            }
            if (!IsLeapYear(year)) {
                return (false);
            }
            if (month == 2 && day == 29) {
                return (true);
            }
            return (false);
        }

 public void PosTest2()
 {
     System.Globalization.Calendar myCalendar = new GregorianCalendar(GregorianCalendarTypes.USEnglish);
     int year, month, day;
     bool expectedValue;
     bool actualValue;
     year = GetACommonYear(myCalendar);
     month = 2;
     day = 28;
     expectedValue = false;
     actualValue = myCalendar.IsLeapDay(year, month, day, 1);
     Assert.Equal(expectedValue, actualValue);
 }