Duplicity exits with the following message after an otherwise successful run:

  ('Could not unlock the acquired lock opened on `%s`',
b'DuplicityArchive/2019-03-17T19:50:06-07:00-Differential/lockfile')
Traceback (most recent call last):
    File "/usr/lib/python3.8/site-packages/fasteners/process_lock.py", line
166, in release
      self.unlock()
    File "/usr/lib/python3.8/site-packages/fasteners/process_lock.py", line
193, in unlock
      self._unlock(self.lockfile)
    File "/usr/lib/python3.8/site-packages/fasteners/process_lock.py", line
430, in _unlock
      fcntl.lockf(lockfile, fcntl.LOCK_UN)
  TypeError: argument must be an int, or have a fileno() method.

I believe this started after the recent upgrade to python38-fasteners
0.16.1-1.1.

Note, this occurs on both x86-64 and aarch64.