public function calendar(): CalendarInterface
    {
        $non_gregorian_calendars = [
            'ar' => new ArabicCalendar(),
            'fa' => new PersianCalendar(),
            'he' => new JewishCalendar(),
            'yi' => new JewishCalendar(),
        ];

        return $non_gregorian_calendars[$this->locale->languageTag()] ?? new GregorianCalendar();
    }