code: function(year, month, day) {
  			this._validateLevel++;
  			var valid = (this.hasYearZero || year !== 0);
  			if (valid) {
  				var date = this.newDate(year, month, this.minDay);
  				valid = (month >= this.minMonth && month - this.minMonth < this.monthsInYear(date)) &&
  					(day >= this.minDay && day - this.minDay < this.daysInMonth(date));
  			}
  			this._validateLevel--;
  			return valid;
  		}
docs: Determine whether a date is valid for this calendar.
  @memberof BaseCalendar
  @param year {number} The year to examine.
  @param month {number} The month to examine.
  @param day {number} The day to examine.
  @return {boolean} <code>true</code> if a valid date, <code>false</code> if not.