#!/usr/bin/python
import dbus
bus = dbus.Bus(dbus.Bus.TYPE_SESSION)
devobj = bus.get_object('org.gnome.PowerManager', '/org/gnome/PowerManager')
dev = dbus.Interface(devobj, "org.gnome.PowerManager")
cookie = dev.Inhibit('Nautilus', 'Copying files')
#do something 
dev.UnInhibit(cookie)

##</code><code>##

use Net::DBus;

#get the session bus
my $bus = Net::DBus->session;

#Get the Gnome power manager object === Wrong!!!
my $devobj = $bus->get_object("/org/gnome/PowerManager", "org.gnome.PowerManager");

#Get the interface === Wrong!!!
my $dev = $bus->Interface($devobj,"org.gnome.PowerManager");

my $cookie = $dev->Inhibit("Squeezecenter", "Playing");
.... more code
$dev->UnInhibit($cookie);

1;