102 lines
3.1 KiB
Python
102 lines
3.1 KiB
Python
# cfi.py - functions for handling ISIN numbers
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#
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# Copyright (C) 2022 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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"""CFI (ISO 10962 Classification of Financial Instruments).
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The CFI is a 6-character code used to classify financial instruments. It is
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issued alongside an ISIN and describes category such as equity or future and
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category-specific properties such as underlying asset type or payment status.
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More information:
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* https://en.wikipedia.org/wiki/ISO_10962
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* https://www.iso.org/standard/73564.html
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* https://www.six-group.com/en/products-services/financial-information/data-standards.html
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>>> validate('ELNUFR')
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'ELNUFR'
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>>> validate('ELNUFQ')
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Traceback (most recent call last):
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...
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InvalidComponent: ...
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>>> import json
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>>> print(json.dumps(info('ELNUFR'), indent=2, sort_keys=True))
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{
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"Form": "Registered",
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"Ownership/transfer/sales restrictions": "Free",
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"Payment status": "Fully paid",
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"Voting right": "Non-voting",
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"category": "Equities",
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"group": "Limited partnership units"
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}
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"""
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from __future__ import annotations
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from stdnum import numdb
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from stdnum.exceptions import *
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from stdnum.util import clean
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# our open copy of the CFI database
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_cfidb = numdb.get('cfi')
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def compact(number: str) -> str:
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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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def info(number: str) -> dict[str, str]:
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"""Look up information about the number."""
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number = compact(number)
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info = _cfidb.info(number)
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if len(info) != 6:
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raise InvalidComponent()
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properties = {}
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properties.update(info[0][1])
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properties.update(info[1][1])
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for nr, found in info[2:]:
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if nr != 'X' and 'v' not in found:
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raise InvalidComponent()
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if 'v' in found:
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properties[found['a']] = found['v']
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return properties
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def validate(number: str) -> str:
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"""Check if the number provided is valid. This checks the length and
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format."""
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number = compact(number)
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if not all(x in 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 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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info(number)
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return number
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def is_valid(number: str) -> bool:
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"""Check if the number provided is valid. This checks the length and
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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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