python test.py 
Traceback (most recent call last):
  File "test.py", line 120, in <module>
    TestApp()
  File "test.py", line 20, in __init__
    session_bus = dbus.SessionBus()
  File "/usr/lib/python2.5/site-packages/dbus/_dbus.py", line 669, in __new__
    mainloop=mainloop)
  File "/usr/lib/python2.5/site-packages/dbus/_dbus.py", line 293, in __new__
    mainloop=mainloop)
dbus.DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.