public function dayNames(int $day_number): string
    {
        static $translated_day_names;

        if ($translated_day_names === null) {
            $translated_day_names = [
                0 => I18N::translate('Monday'),
                1 => I18N::translate('Tuesday'),
                2 => I18N::translate('Wednesday'),
                3 => I18N::translate('Thursday'),
                4 => I18N::translate('Friday'),
                5 => I18N::translate('Saturday'),
                6 => I18N::translate('Sunday'),
            ];
        }

        return $translated_day_names[$day_number];
    }