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# rnc.py - functions for handling Dominican Republic tax registration
#
# 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
"""RNC (Registro Nacional del Contribuyente, Dominican Republic tax number).
The RNC is the Dominican Republic taxpayer registration number for
institutions. The number consists of 9 digits.
>>> validate('1-01-85004-3')
'101850043'
>>> validate('1018A0043')
Traceback (most recent call last):
...
InvalidFormat: ...
>>> validate('101850042')
Traceback (most recent call last):
...
InvalidChecksum: ...
>>> format('131246796')
'1-31-24679-6'
"""
from stdnum.exceptions import *
from stdnum.util import clean
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_check_digit(number):
"""Calculate the check digit."""
weights = (7, 9, 8, 6, 5, 4, 3, 2)
check = sum(w * int(n) for w, n in zip(weights, number)) % 11
return str((10 - check) % 9 + 1)
def validate(number):
"""Check if the number provided is a valid RNC."""
number = compact(number)
if len(number) != 9:
raise InvalidLength()
if not number.isdigit():
raise InvalidFormat()
if calc_check_digit(number[:-1]) != number[-1]:
raise InvalidChecksum()
return number
def is_valid(number):
"""Check if the number provided is a valid RNC."""
try:
return bool(validate(number))
except ValidationError:
return False
def format(number):
"""Reformat the number to the standard presentation format."""
number = compact(number)
return '-'.join((number[:1], number[1:3], number[3:-1], number[-1]))
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