Traceback (most recent call last):
  File "/usr/lib/ubuntu-release-upgrader/check-new-release-gtk", line 43, in <module>
    from DistUpgrade.DistUpgradeFetcher import DistUpgradeFetcherGtk
  File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcher.py", line 24, in <module>
    gi.require_version("Gtk", "3.0")
  File "/usr/lib/python3/dist-packages/gi/__init__.py", line 117, in require_version
    raise ValueError('Namespace %s is already loaded with version %s' %
ValueError: Namespace Gtk is already loaded with version 4.0