Comment 7 for bug 1945661

I just upgraded my test environment from Victoria to Wallaby (Ubuntu 20.04, our own package based deployment, no kolla/ansible etc. involved) and now I'm seeing the same error message when trying to use the openstack cli:

root@control01:~# openstack network agent list
Traceback (most recent call last):
  File "/usr/bin/openstack", line 6, in <module>
    from openstackclient.shell import main
  File "/usr/lib/python3/dist-packages/openstackclient/shell.py", line 23, in <module>
    from osc_lib import shell
  File "/usr/lib/python3/dist-packages/osc_lib/shell.py", line 24, in <module>
    from cliff import app
  File "/usr/lib/python3/dist-packages/cliff/app.py", line 22, in <module>
    import cmd2
  File "/usr/lib/python3/dist-packages/cmd2.py", line 585, in <module>
    _ = pyperclip.paste()
  File "/usr/lib/python3/dist-packages/pyperclip/__init__.py", line 667, in lazy_load_stub_paste
    copy, paste = determine_clipboard()
  File "/usr/lib/python3/dist-packages/pyperclip/__init__.py", line 558, in determine_clipboard
    return init_gi_clipboard()
  File "/usr/lib/python3/dist-packages/pyperclip/__init__.py", line 167, in init_gi_clipboard
    gi.require_version('Gtk', '3.0')
  File "/usr/lib/python3/dist-packages/gi/__init__.py", line 129, in require_version
    raise ValueError('Namespace %s not available' % namespace)
ValueError: Namespace Gtk not available