w00kie

#!/usr/bin/env python
# encoding: utf-8
"""
checkdigit.py
-------------
Check validity of parcel tracking number from Yamato, Sagawa and JapanPost Yu-pack.
Using the "seven check" method described on http://okwave.jp/qa/q1785259.html
Apply the weights 46231546231 to each digit but the last. Sum it all up and divide by 7.
Remainder must be equal to the last digit of the tracking number.