hashes.luhn
===========

.. py:module:: hashes.luhn

.. autoapi-nested-parse::

   Luhn Algorithm



Functions
---------

.. autoapisummary::

   hashes.luhn.is_luhn


Module Contents
---------------

.. py:function:: is_luhn(string: str) -> bool

   Perform Luhn validation on an input string
   Algorithm:
   * Double every other digit starting from 2nd last digit.
   * Subtract 9 if number is greater than 9.
   * Sum the numbers
   *
   >>> test_cases = (79927398710, 79927398711, 79927398712, 79927398713,
   ...     79927398714, 79927398715, 79927398716, 79927398717, 79927398718,
   ...     79927398719)
   >>> [is_luhn(str(test_case)) for test_case in test_cases]
   [False, False, False, True, False, False, False, False, False, False]