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# figi.py - functions for handling FIGI numbers
#
# Copyright (C) 2018 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
"""FIGI (Financial Instrument Global Identifier).
The Financial Instrument Global Identifier (FIGI) is a 12-character
alpha-numerical unique identifier of financial instruments such as common
stock, options, derivatives, futures, corporate and government bonds,
municipals, currencies, and mortgage products.
More information:
* https://openfigi.com/
* https://en.wikipedia.org/wiki/Financial_Instrument_Global_Identifier
>>> validate('BBG000BLNQ16')
'BBG000BLNQ16'
>>> validate('BBG000BLNQ14')
Traceback (most recent call last):
...
InvalidChecksum: ...
"""
from stdnum.exceptions import *
from stdnum.util import clean, isdigits
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().upper()
def calc_check_digit(number):
"""Calculate the check digits for the number."""
# we use the full alphabet for the check digit calculation
alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
# convert to numeric first, then double some, then sum individual digits
number = ''.join(
str(alphabet.index(n) * (1, 2)[i % 2])
for i, n in enumerate(number[:11]))
return str((10 - sum(int(n) for n in number)) % 10)
def validate(number):
"""Check if the number provided is a valid FIGI."""
number = compact(number)
if not all(x in '0123456789BCDFGHJKLMNPQRSTVWXYZ' for x in number):
raise InvalidFormat()
if len(number) != 12:
raise InvalidLength()
if isdigits(number[0]) or isdigits(number[1]):
raise InvalidFormat()
if number[:2] in ('BS', 'BM', 'GG', 'GB', 'VG'):
raise InvalidComponent()
if number[2] != 'G':
raise InvalidComponent()
if calc_check_digit(number[:-1]) != number[-1]:
raise InvalidChecksum()
return number
def is_valid(number):
"""Check if the number provided is a valid FIGI."""
try:
return bool(validate(number))
except ValidationError:
return False
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