IBAN\Core\IBAN::isChecksumValid PHP Method

    private function isChecksumValid()
    {
        $localeCode = $this->getLocaleCode();
        $checksum = $this->getChecksum();
        $accountIdentification = $this->getAccountIdentification();
        $numericLocalCode = $this->getNumericLocaleCode($localeCode);
        $numericAccountIdentification = $this->getNumericAccountIdentification($accountIdentification);
        $invertedIban = $numericAccountIdentification . $numericLocalCode . $checksum;
        return $this->local_bcmod($invertedIban, 97) === '1';
    }