public static function getCountryMobileToken($countryCallingCode)
    {
        if (count(static::$MOBILE_TOKEN_MAPPINGS) === 0) {
            static::initMobileTokenMappings();
        }

        if (array_key_exists($countryCallingCode, static::$MOBILE_TOKEN_MAPPINGS)) {
            return static::$MOBILE_TOKEN_MAPPINGS[$countryCallingCode];
        }
        return '';
    }