# stdnum.ch.uid

UID (Unternehmens-Identifikationsnummer, Swiss business identifier).

The Swiss UID is used to uniquely identify businesses for taxation purposes. The number consists of a fixed “CHE” prefix, followed by 9 digits that are protected with a simple checksum.

This module only supports the “new” format that was introduced in 2011 which completely replaced the “old” 6-digit format in 2014.

More information:

- https://www.uid.admin.ch/
- https://de.wikipedia.org/wiki/Unternehmens-Identifikationsnummer

    >>> validate('CHE-100.155.212')
    'CHE100155212'
    >>> validate('CHE-100.155.213')
    Traceback (most recent call last):
        ...
    InvalidChecksum: ...
    >>> format('CHE100155212')
    'CHE-100.155.212'

`stdnum.ch.uid.``calc_check_digit`(number)

  Calculate the check digit for organisations. The number passed should not have the check digit included.

`stdnum.ch.uid.``compact`(number)

  Convert the number to the minimal representation. This strips surrounding whitespace and separators.

`stdnum.ch.uid.``format`(number)

  Reformat the number to the standard presentation format.

`stdnum.ch.uid.``is_valid`(number)

  Check if the number is a valid UID.

`stdnum.ch.uid.``validate`(number)

  Check if the number is a valid UID. This checks the length, formatting and check digit.