protected function formatFractionalPart(
        $value,
        $fractional_digits,
        SwatI18NNumberFormat $format
    ) {
        if ($fractional_digits === 0) {
            $formatted_value = '';
        } else {
            $frac_part = abs(fmod($value, 1));
            $frac_part = round($frac_part * pow(10, $fractional_digits));
            $frac_part = str_pad(
                $frac_part,
                $fractional_digits,
                '0',
                STR_PAD_LEFT
            );

            $formatted_value = $format->decimal_separator . $frac_part;
        }

        return $formatted_value;
    }