private function verifyMod10($input): bool
    {
        $sum = 0;
        $input = strrev($input);
        $inputLen = \strlen($input);
        for ($i = 0; $i < $inputLen; $i++) {
            $current = $input[$i];
            if ($i % 2 === 1) {
                $current *= 2;
                if ($current > 9) {
                    $firstDigit = $current % 10;
                    $secondDigit = ($current - $firstDigit) / 10;
                    $current = $firstDigit + $secondDigit;
                }
            }
            $sum += $current;
        }

        return ($sum % 10 === 0);
    }