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# 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 __future__ import annotations
from stdnum.exceptions import *
from stdnum.util import clean, isdigits
def compact(number: str) -> str:
"""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: str) -> int:
"""Calculate the checksum."""
return (int(number[:-2]) + int(number[-2:])) % 97
def validate(number: str) -> str:
"""Check if the number is a valid VAT number. This checks the length,
formatting and check digit."""
number = compact(number)
if not isdigits(number) or int(number) <= 0:
raise InvalidFormat()
if len(number) != 10:
raise InvalidLength()
if checksum(number) != 0:
raise InvalidChecksum()
return number
def is_valid(number: str) -> bool:
"""Check if the number is a valid VAT number."""
try:
return bool(validate(number))
except ValidationError:
return False
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