1# lei.py - functions for handling Legal Entity Identifiers (LEIs)
2# coding: utf-8
3#
4# Copyright (C) 2017 Arthur de Jong
5#
6# This library is free software; you can redistribute it and/or
7# modify it under the terms of the GNU Lesser General Public
8# License as published by the Free Software Foundation; either
9# version 2.1 of the License, or (at your option) any later version.
10#
11# This library is distributed in the hope that it will be useful,
12# but WITHOUT ANY WARRANTY; without even the implied warranty of
13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14# Lesser General Public License for more details.
15#
16# You should have received a copy of the GNU Lesser General Public
17# License along with this library; if not, write to the Free Software
18# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19# 02110-1301 USA
20
21"""LEI (Legal Entity Identifier).
22
23The Legal Entity Identifier (LEI) is used to identify legal entities for use
24in financial transactions. A LEI is a 20-character alphanumeric string that
25consists of a 4-character issuing LOU (Local Operating Unit), 2 digits that
26are often 0, 13 digits to identify the organisation and 2 check digits.
27
28More information:
29
30* https://en.wikipedia.org/wiki/Legal_Entity_Identifier
31* http://www.lei-lookup.com/
32* https://www.gleif.org/
33* http://openleis.com/
34
35>>> validate('213800KUD8LAJWSQ9D15')
36'213800KUD8LAJWSQ9D15'
37>>> validate('213800KUD8LXJWSQ9D15')
38Traceback (most recent call last):
39    ...
40InvalidChecksum: ...
41"""
42
43from stdnum.exceptions import *
44from stdnum.iso7064 import mod_97_10
45from stdnum.util import clean
46
47
48def compact(number):
49    """Convert the number to the minimal representation. This strips the
50    number of any valid separators and removes surrounding white space."""
51    return clean(number, ' -').strip().upper()
52
53
54def validate(number):
55    """Check if the number is valid. This checks the length, format and check
56    digits."""
57    number = compact(number)
58    mod_97_10.validate(number)
59    return number
60
61
62def is_valid(number):
63    """Check if the number is valid."""
64    try:
65        return bool(validate(number))
66    except ValidationError:
67        return False
68