# stdnum.iso11649

ISO 11649 (Structured Creditor Reference).

The ISO 11649 structured creditor number consists of ‘RF’ followed by two check digits and up to 21 digits. The number may contain letters.

The reference number is validated by moving RF and the check digits to the end of the number, and checking that the ISO 7064 Mod 97, 10 checksum of this string is 1.

More information:

- https://en.wikipedia.org/wiki/Creditor_Reference

    >>> validate('RF18 5390 0754 7034')
    'RF18539007547034'
    >>> validate('RF18 5390 0754 70Y')
    'RF185390075470Y'
    >>> is_valid('RF18 5390 0754 7034')
    True
    >>> validate('RF17 5390 0754 7034')
    Traceback (most recent call last):
        ...
    InvalidChecksum: ...
    >>> format('RF18539007547034')
    'RF18 5390 0754 7034'

`stdnum.iso11649.``compact`(number)

  Convert the number to the minimal representation. This strips the number of any invalid separators and removes surrounding whitespace.

`stdnum.iso11649.``format`(number)

  Format the number provided for output.

  Blocks of 4 characters, the last block can be less than 4 characters. See https://www.paymentstandards.ch/dam/downloads/ig-qr-bill-en.pdf chapter 3.6.2.

`stdnum.iso11649.``is_valid`(number)

  Check if the number provided is a valid ISO 11649 structured creditor number. This checks the length, formatting and check digits.

`stdnum.iso11649.``validate`(number)

  Check if the number provided is a valid ISO 11649 structured creditor reference number.