code: function(year) {
  			var date = this._validate(year, this.minMonth, this.minDay,
  				$.calendars.local.invalidYear || $.calendars.regionalOptions[''].invalidYear);
  			var year = date.year() + (date.year() < 0 ? 1 : 0); // No year zero
  			return year % 4 === 0 && (year % 100 !== 0 || year % 400 === 0);
  		}
docs: Determine whether this date is in a leap year.
  @memberof GregorianCalendar
  @param year {CDate|number} The date to examine or the year to examine.
  @return {boolean} <code>true</code> if this is a leap year, <code>false</code> if not.
  @throws Error if an invalid year or a different calendar used.