--- vncviewer.py
#!/usr/bin/python

import sys, gtk, gtkvnc

screen = gtkvnc.Display()
screen.open_host("192.168.0.102", "5900")
win = gtk.Window()
win.add(screen)
win.connect("delete-event", lambda w,e: quit())
win.show_all()
gtk.main()

--- vncviewer.py3
#!/usr/bin/python3

import sys, gi
gi.require_version('Gtk', '3.0')
gi.require_version('GtkVnc', '2.0')
from gi.repository import Gtk, Gdk, GLib, GtkVnc

screen = GtkVnc.Display()
screen.open_host("192.168.0.102", "5900")
win = Gtk.Window()
win.add(screen)
win.connect("delete-event", lambda w,e: quit())
win.show_all()
Gtk.main()
