sudo software-properties-gtk
Traceback (most recent call last):
  File "/usr/bin/software-properties-gtk", line 25, in <module>
    from gi.repository import Gtk
  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 224, in _load
    overrides_modules = __import__('gi.overrides', fromlist=[self._namespace])
  File "/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py", line 1533, in <module>
    raise RuntimeError("Gtk couldn't be initialized")
RuntimeError: Gtk couldn't be initialized