Comment 8 for bug 1967793

A possible fix would be to backport https://github.com/shlomif/PySolFC/commit/79d27d2749c906040073909a2a7c1162282b806c.

In the long run, ideally, we should move away from the formatter module, since it has been deprecated since python 3.5 and it is not well tested. Moreover, we should (ideally) update the package to a more recent version in Debian.

Due to the patch linked above, debian/copyright should also be updated to include the license for the new formatter port. Therefore, before considering the upstream patch (or updating the Debian package), we should verify if python's 3.9 module is compatible with CC0, as it was licensed by pysolfc upstream.

Looking at https://github.com/python/cpython/blob/3.9/Lib/formatter.py, I see no license headers. I then assume it is licensed under the Python Software Foundation License Version 2, as the rest of the code in that repository.

While I am not a lawyer, these 2 bits from the PSF license may concert pysolfc upstream regarding the embedded formatter file:

2. Subject to the terms and conditions of this License Agreement, PSF hereby
grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
analyze, test, perform and/or display publicly, prepare derivative works,
distribute, and otherwise use Python alone or in any derivative version,
provided, however, that PSF's License Agreement and PSF's notice of copyright,
i.e., "Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 Python Software Foundation;
All Rights Reserved" are retained in Python alone or in any derivative version
prepared by Licensee.

3. In the event Licensee prepares a derivative work that is based on
or incorporates Python or any part thereof, and wants to make
the derivative work available to others as provided herein, then
Licensee hereby agrees to include in any such work a brief summary of
the changes made to Python.