code: function CDate(calendar, year, month, day) {
  		this._calendar = calendar;
  		this._year = year;
  		this._month = month;
  		this._day = day;
  		if (this._calendar._validateLevel === 0 &&
  				!this._calendar.isValid(this._year, this._month, this._day)) {
  			throw ($.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate).
  				replace(/\{0\}/, this._calendar.local.name);
  		}
  	}
docs: Generic date, based on a particular calendar.
  @class CDate
  @param calendar {BaseCalendar} The underlying calendar implementation.
  @param year {number} The year for this date.
  @param month {number} The month for this date.
  @param day {number} The day for this date.
  @return {CDate} The date object.
  @throws Error if an invalid date.