Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 527, in on_checkbutton_popcon_toggled
    self.backend.SetPopconPariticipation(widget.get_active())
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 145, in __call__
    **keywords)
  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 651, in call_blocking
    message, timeout)
DBusException: org.freedesktop.DBus.Python.AttributeError: Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/dbus/service.py", line 702, in _message_cb
    keywords[parent_method._dbus_message_keyword] = message
  File "/usr/lib/python2.7/dist-packages/softwareproperties/dbus/SoftwarePropertiesDBus.py", line 226, in SetPopconPariticipation
    sender, conn, "com.ubuntu.softwareproperties.applychanges")
  File "/usr/lib/python2.7/dist-packages/softwareproperties/dbus/SoftwarePropertiesDBus.py", line 347, in _check_policykit_privilege
    return self._check_polkit_privilege(sender, conn, privilege)
AttributeError: 'SoftwarePropertiesDBus' object has no attribute '_check_polkit_privilege'