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# cuit.py - functions for handling Argentinian VAT numbers
# coding: utf-8
#
# Copyright (C) 2009 Mariano Reingart
# Copyright (C) 2011 Sebastián Marró
# Copyright (C) 2008-2011 Cédric Krier
# Copyright (C) 2008-2011 B2CK
# Copyright (C) 2015 Arthur de Jong
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
"""CUIT (Código Único de Identificación Tributaria, Argentinian tax number).
The CUIT is a taxpayer identification number used for VAT (IVA, Impuesto al
Valor Agregado) and other taxes.
>>> validate('200-5536168-2')
'20055361682'
>>> validate('2026756539')
Traceback (most recent call last):
...
InvalidLength: ...
>>> validate('2026756A393')
Traceback (most recent call last):
...
InvalidFormat: ...
>>> validate('20267565392')
Traceback (most recent call last):
...
InvalidChecksum: ...
"""
from stdnum.exceptions import *
from stdnum.util import clean
def compact(number):
"""Convert the number to the minimal representation. This strips the
number of any valid separators and removes surrounding whitespace."""
return clean(number, ' -').strip()
def calc_check_digit(number):
"""Calculate the check digit."""
weights = (5, 4, 3, 2, 7, 6, 5, 4, 3, 2)
check = sum(w * int(n) for w, n in zip(weights, number)) % 11
return '012345678990'[11 - check]
def validate(number):
"""Checks to see if the number provided is a valid CUIT."""
number = compact(number)
if len(number) != 11:
raise InvalidLength()
if not number.isdigit():
raise InvalidFormat()
if calc_check_digit(number[:-1]) != number[-1]:
raise InvalidChecksum()
return number
def is_valid(number):
"""Checks to see if the number provided is a valid CUIT."""
try:
return bool(validate(number))
except ValidationError:
return False
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