protected function throwNumberFormatterException(IntlNumberFormatter $intlFormatter, $number): void
    {
        $error_code = $intlFormatter->getErrorCode();
        if (is_scalar($number)) {
            $val = (string) $number;
        } else {
            $val = 'type: ' . gettype($number);
        }
        throw new Exception\RuntimeException(__METHOD__ . " Cannot format value '$val', Intl/NumberFormatter error code: $error_code.");
    }