import dbus
bus = dbus.bus.BusConnection("unix:path=/var/run/dbus/system_bus_socket")
object = bus.get_object('com.nokia.mce', '/com/nokia/mce/request')
interface = dbus.Interface(object, dbus_interface='com.nokia.mce.request')
interface.devlock_callback(dbus.Int32("2"))

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/pymodules/python2.5/dbus/proxies.py", line 68, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib/pymodules/python2.5/dbus/proxies.py", line 140, in __call__
    **keywords)
  File "/usr/lib/pymodules/python2.5/dbus/connection.py", line 622, in call_blocking
    message, timeout)
dbus.exceptions.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.