74 lines
2.3 KiB
Python
74 lines
2.3 KiB
Python
# wkn.py - functions for handling Wertpapierkennnummer
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# coding: utf-8
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#
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# Copyright (C) 2015 Arthur de Jong
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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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"""Wertpapierkennnummer (German securities identification code).
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The WKN, WPKN, WPK (Wertpapierkennnummer) is a German code to identify
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securities. It is a 6-digit alphanumeric number without a check digit that no
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longer has any structure. It is expected to be replaced by the ISIN.
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>>> validate('A0MNRK')
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'A0MNRK'
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>>> validate('AOMNRK') # no capital o allowed
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Traceback (most recent call last):
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...
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InvalidFormat: ...
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>>> to_isin('SKWM02')
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'DE000SKWM021'
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"""
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from stdnum.exceptions import *
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from stdnum.util import clean
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def compact(number):
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"""Convert the number to the minimal representation. This strips the
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number of any valid separators and removes surrounding whitespace."""
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return clean(number, ' ').strip().upper()
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# O and I are not valid but are accounted for in the check digit calculation
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_alphabet = '0123456789ABCDEFGH JKLMN PQRSTUVWXYZ'
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def validate(number):
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"""Checks to see if the number provided is valid. This checks the length
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and check digit."""
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number = compact(number)
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if not all(x in _alphabet for x in number):
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raise InvalidFormat()
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if len(number) != 6:
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raise InvalidLength()
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return number
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def is_valid(number):
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"""Checks to see if the number provided is valid. This checks the length
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and check digit."""
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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 to_isin(number):
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"""Convert the number to an ISIN."""
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from stdnum import isin
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return isin.from_natid('DE', number)
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