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