code: function(year, month, day) {
  			return this._calendar.newDate((year == null ? this : year), month, day);
  		}
docs: Create a new date.
  @memberof CDate
  @param [year] {CDate|number} The date to copy or the year for the date (default this date).
  @param [month] {number} The month for the date.
  @param [day] {number} The day for the date.
  @return {CDate} The new date.
  @throws Error if an invalid date.