94 lines
3.1 KiB
Python
94 lines
3.1 KiB
Python
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# inn.py - functions for handling Russian VAT numbers
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# coding: utf-8
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#
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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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"""ИНН (Идентификационный номер налогоплательщика, Russian tax identifier).
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The Indentifikatzionny nomer nalogoplatel'shchika is a Russian tax
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identification number that consists 10 digits for companies and 12 digits for
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persons.
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>>> validate('123456789047')
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'123456789047'
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>>> validate('1234567894')
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'1234567894'
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>>> validate('123456789037')
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Traceback (most recent call last):
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...
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InvalidChecksum: ...
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>>> validate('1234567895')
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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_company_check_digit(number):
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"""Calculate the check digit for the 10-digit ИНН for organisations."""
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weights = (2, 4, 10, 3, 5, 9, 4, 6, 8)
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return str(sum(weights[i] * int(n)
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for i, n in enumerate(number[:9])) % 11 % 10)
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def calc_personal_check_digits(number):
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"""Calculate the check digits for the 12-digit personal ИНН."""
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weights = (7, 2, 4, 10, 3, 5, 9, 4, 6, 8)
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d1 = str(sum(weights[i] * int(n)
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for i, n in enumerate(number[:10])) % 11 % 10)
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weights = (3, 7, 2, 4, 10, 3, 5, 9, 4, 6, 8)
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d2 = str(sum(weights[i] * int(n)
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for i, n in enumerate(number[:10] + d1)) % 11 % 10)
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return d1 + d2
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def validate(number):
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"""Checks to see if the number provided is a valid ИНН. This checks the
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length, formatting and check digit."""
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number = compact(number)
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if not number.isdigit():
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raise InvalidFormat()
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if len(number) == 10:
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if calc_company_check_digit(number) != number[-1]:
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raise InvalidChecksum()
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elif len(number) == 12:
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# persons
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if calc_personal_check_digits(number) != number[-2:]:
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raise InvalidChecksum()
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else:
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raise InvalidLength()
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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 ИНН. This checks the
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length, formatting and check digit."""
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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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