def check_vat_nl(self, vat): """ Temporary Netherlands VAT validation to support the new format introduced in January 2020, until upstream is fixed. Algorithm detail: http://kleineondernemer.nl/index.php/nieuw-btw-identificatienummer-vanaf-1-januari-2020-voor-eenmanszaken TODO: remove when fixed upstream """ try: from stdnum.util import clean from stdnum.nl.bsn import checksum except ImportError: return True vat = clean(vat, ' -.').upper().strip() # Remove the prefix if vat.startswith("NL"): vat = vat[2:] if not len(vat) == 12: return False # Check the format match = self.__check_vat_nl_re.match(vat) if not match: return False # Match letters to integers char_to_int = {k: str(ord(k) - 55) for k in string.ascii_uppercase} char_to_int['+'] = '36' char_to_int['*'] = '37' # 2 possible checks: # - For natural persons # - For non-natural persons and combinations of natural persons (company) # Natural person => mod97 full checksum check_val_natural = '2321' for x in vat: check_val_natural += x if x.isdigit() else char_to_int[x] if int(check_val_natural) % 97 == 1: return True # Company => weighted(9->2) mod11 on bsn vat = vat[:-3] if vat.isdigit() and checksum(vat) == 0: return True return False
def validate(number): """Check if the number is a valid onderwijsnummer. This checks the length and whether the check digit is correct and whether it starts with the right sequence.""" number = compact(number) if not number.isdigit() or int(number) <= 0: raise InvalidFormat() if not number.startswith('10'): raise InvalidFormat() if len(number) != 9: raise InvalidLength() if checksum(number) != 5: raise InvalidChecksum() return number