public function getExampleShortNumberForCost($regionCode, $cost)
    {
        $phoneMetadata = $this->getMetadataForRegion($regionCode);
        if ($phoneMetadata === null) {
            return '';
        }

        /** @var PhoneNumberDesc $desc */
        $desc = null;
        switch ($cost) {
            case ShortNumberCost::TOLL_FREE:
                $desc = $phoneMetadata->getTollFree();
                break;
            case ShortNumberCost::STANDARD_RATE:
                $desc = $phoneMetadata->getStandardRate();
                break;
            case ShortNumberCost::PREMIUM_RATE:
                $desc = $phoneMetadata->getPremiumRate();
                break;
            default:
                // UNKNOWN_COST numbers are computed by the process of elimination from the other cost categories
                break;
        }

        if ($desc !== null && $desc->hasExampleNumber()) {
            return $desc->getExampleNumber();
        }

        return '';
    }