88 lines
2.6 KiB
Python
88 lines
2.6 KiB
Python
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# tin.py - functions for handling South Africa Tax Reference Number
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# coding: utf-8
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#
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# Copyright (C) 2019 Leandro Regueiro
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301 USA
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"""TIN (South African Tax Identification Number).
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The South African Tax Identification Number (TIN or Tax Reference Number) is
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issued to individuals and legal entities for tax purposes. The number
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consists of 10 digits.
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More information:
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* https://www.oecd.org/tax/automatic-exchange/crs-implementation-and-assistance/tax-identification-numbers/South-Africa-TIN.pdf
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* https://www.sars.gov.za/
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>>> validate('0001339050')
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'0001339050'
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>>> validate('2449/494/16/0')
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Traceback (most recent call last):
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...
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InvalidChecksum: ...
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>>> validate('9125568')
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Traceback (most recent call last):
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...
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InvalidLength: ...
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>>> format('084308984-8')
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'0843089848'
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""" # noqa: E501
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from __future__ import annotations
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from stdnum import luhn
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from stdnum.exceptions import *
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from stdnum.util import clean, isdigits
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def compact(number: str) -> str:
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"""Convert the number to the minimal representation.
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This strips the number of any valid separators and removes surrounding
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whitespace.
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"""
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return clean(number, ' -/').upper().strip()
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def validate(number: str) -> str:
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"""Check if the number is a valid South Africa Tax Reference Number.
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This checks the length, formatting and check digit.
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"""
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number = compact(number)
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if len(number) != 10:
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raise InvalidLength()
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if not isdigits(number):
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raise InvalidFormat()
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if number[0] not in '01239':
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raise InvalidComponent()
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return luhn.validate(number)
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def is_valid(number: str) -> bool:
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"""Check if the number is a valid South Africa Tax Reference Number."""
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try:
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return bool(validate(number))
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except ValidationError:
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return False
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def format(number: str) -> str:
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"""Reformat the number to the standard presentation format."""
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return compact(number)
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