$ python3
Python 3.6.5 (default, Aug 30 2018, 15:41:16) 
[GCC 7.3.1 20180712 (ALT 7.3.1-alt5)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import keyring
>>> keyring.set_password("test","test","test")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3/site-packages/keyring/core.py", line 47, in set_password
    _keyring_backend.set_password(service_name, username, password)
  File "/usr/lib/python3/site-packages/keyring/backends/fail.py", line 23, in get_password
    raise RuntimeError(msg)
RuntimeError: No recommended backend was available. Install the keyrings.alt package if you want to use the non-recommended backends. See README.rst for details.

Если запускать исполняемый файл из пакета:
$ keyring.py3 set "test" "test" "test"
Traceback (most recent call last):
  File "/usr/bin/keyring.py3", line 6, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 3123, in <module>
    @_call_aside
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 3107, in _call_aside
    f(*args, **kwargs)
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 3136, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 578, in _build_master
    ws.require(__requires__)
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 895, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 781, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'secretstorage' distribution was not found and is required by keyring

После установки python3-module-keyring:
$ python3
Python 3.6.5 (default, Aug 30 2018, 15:41:16) 
[GCC 7.3.1 20180712 (ALT 7.3.1-alt5)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import keyring
>>> keyring.set_password("test","test","test")
>>> 

Правда, keyring.py3 затем ругается на другой модуль (хотя он и установлен):
$ keyring.py3 set "test" "test" "test"
Traceback (most recent call last):
  File "/usr/bin/keyring.py3", line 6, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 3123, in <module>
    @_call_aside
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 3107, in _call_aside
    f(*args, **kwargs)
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 3136, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 578, in _build_master
    ws.require(__requires__)
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 895, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python3/site-packages/pkg_resources/__init__.py", line 781, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'entrypoints' distribution was not found and is required by keyring