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