protected function getRegionDisplayName($regionCode, $locale)
    {
        if ($regionCode === null || $regionCode == 'ZZ' || $regionCode === PhoneNumberUtil::REGION_CODE_FOR_NON_GEO_ENTITY) {
            return '';
        }

        return Locale::getDisplayRegion(
            '-' . $regionCode,
            $locale
        );
    }