Trying introspect with python bindings

[Tako Schotanus]

Using the latest CVS version I changed the list-system-services.py 
(which might be renamed to list-sytem-names.py) to try to let it return 
the introspection data for the DBus object but without any luck. This is 
what the (extra) code looks like:

   dbus_info = dbus_service.get_object('/org/freedesktop/DBus', 
'org.freedesktop.Introspectable')
   introspect = dbus_info.Introspect()
   print str(introspect)

and this is what it returns:

   Traceback (most recent call last):
     File "list-session-services.py", line 25, in ?
       introspect = dbus_info.Introspect()
     File "/home/tako/projects/dbus/dbus/python/dbus.py", line 235, in 
__call__
       reply_message = 
self._connection.send_with_reply_and_block(message, 5000)
     File "/home/tako/projects/dbus/dbus/python/dbus_bindings.pyx", line 
524, in dbus_bindings.Connection.send_with_reply_and_block
       raise DBusException, error.message
   dbus_bindings.DBusException: org.freedesktop.DBus does not understand 
message Introspect

it does not give an error in the first line asking the object for its 
interface so I assume DBus implements it (it should, shouldn't it? ;-)).

Does anybody have any idea why this doesn't work?

Thanks,
 -Tako