# vat.py - functions for handling Belgian VAT numbers # # Copyright (C) 2012-2016 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 """BTW, TVA, NWSt, ondernemingsnummer (Belgian enterprise number). The enterprise number (ondernemingsnummer) is a unique identifier of companies within the Belgian administrative services. It was previously the VAT ID number. The number consists of 10 digits. >>> compact('BE403019261') '0403019261' >>> compact('(0)403019261') '0403019261' >>> validate('BE 428759497') '0428759497' >>> validate('BE431150351') 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.""" number = clean(number, ' -./').upper().strip() if number.startswith('BE'): number = number[2:] if number.startswith('(0)'): number = '0' + number[3:] if len(number) == 9: number = '0' + number # old format had 9 digits return number def checksum(number): """Calculate the checksum.""" return (int(number[:-2]) + int(number[-2:])) % 97 def validate(number): """Check if the number is a valid VAT number. This checks the length, formatting and check digit.""" number = compact(number) if not isdigits(number): raise InvalidFormat() if len(number) != 10: raise InvalidLength() if checksum(number) != 0: raise InvalidChecksum() return number def is_valid(number): """Check if the number is a valid VAT number.""" try: return bool(validate(number)) except ValidationError: return False