Как я могу исправить мою установку Ubuntu-Tweak?

Я не могу запустить Ubuntu Tweak. Вроде бы проблема с Python или чем-то еще, но я не уверен.

Вот вывод:

/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py:47: RuntimeWarning: You have imported the Gtk 2.0 module.  Because Gtk 2.0 was not designed for use with introspection some of the interfaces and API will fail.  As such this is not supported by the pygobject development team and we encourage you to port your app to Gtk 3 or greater. PyGTK is the recomended python module to use with Gtk 2.0
  warnings.warn(warn_msg, RuntimeWarning)
Gtk-Message: Failed to load module "rgba"
Traceback (most recent call last):
  File "/usr/bin/ubuntu-tweak", line 53, in <module>
    from ubuntutweak.main import UbuntuTweakApp, UbuntuTweakWindow, show_splash
  File "/usr/lib/python2.7/dist-packages/ubuntutweak/main.py", line 31, in <module>
    from ubuntutweak.gui.dialogs import ErrorDialog
  File "/usr/lib/python2.7/dist-packages/ubuntutweak/gui/dialogs.py", line 21, in <module>
    from gi.repository import GObject, Gtk, Gdk, Pango, Vte
  File "/usr/lib/python2.7/dist-packages/gi/importer.py", line 76, in load_module
    dynamic_module._load()
  File "/usr/lib/python2.7/dist-packages/gi/module.py", line 222, in _load
    version)
  File "/usr/lib/python2.7/dist-packages/gi/module.py", line 90, in __init__
    repository.require(namespace, version)
gi.RepositoryError: Requiring namespace 'Gtk' version '3.0', but '2.0' is already loaded