Convert account number to IBAN

spayd.py

    def _convert_to_iban(self, account):
        """
        Convert czech account number to IBAN
        """
        acc = self.RE_ACCOUNT.match(account)
        iban = 'CZ00{b}{ba:0>6}{a:0>10}'.format(
            ba=acc.group('ba') or 0,
            a=acc.group('a'),
            b=acc.group('b'),
        )

        # convert IBAN letters into numbers
        crc = re.sub(r'[A-Z]', lambda m: str(ord(m.group(0)) - 55), iban[4:] + iban[:4])

        # compute control digits
        digits = "{:0>2}".format(98 - int(crc) % 97)

        return iban[:2] + digits + iban[4:]

nice