docs: public final void showYearMonth(YearMonth yearMonth) {
          requireNonNull(yearMonth);
  
          if (!monthPage.isHidden()) {
              selectedPage.set(getMonthPage());
          } else if (!yearPage.isHidden()) {
              selectedPage.set(getYearPage());
          }
  
          setDate(yearMonth.atDay(1));
      }