code: function(calendar) {
  					while (m < calendar.minMonth) {
  						y--;
  						m += calendar.monthsInYear(y);
  					}
  					var yearMonths = calendar.monthsInYear(y);
  					while (m > yearMonths - 1 + calendar.minMonth) {
  						y++;
  						m -= yearMonths;
  						yearMonths = calendar.monthsInYear(y);
  					}
  				}
docs: + (period === 'd' ? offset : 0) + (period === 'w' ? offset * this.daysInWeek() : 0);