Gtk+Glade+Python

[cambiadeso]

Tengo un error al ejecutar este código:

Código:

#!/usr/bin/env python
import pygtk
pygtk.require('2.0')
import gtk
from gtk import glade
glade.XML('hola.glade')
gtk.main()

(otro.py:18382): libglade-WARNING **: Expected <glade-interface>. Got <interface>.

(otro.py:18382): libglade-WARNING **: did not finish in PARSER_FINISH state
Traceback (most recent call last):
File "otro.py", line 6, in <module>
glade.XML('hola.xml')
RuntimeError: could not create GladeXML object

fichero hola.glade:

Código:

<?xml version="1.0"?>
<interface>
  <requires lib="gtk+" version="2.16"/>
  <!-- interface-naming-policy project-wide -->
  <object class="GtkWindow" id="window1">
    <property name="visible">True</property>
    <property name="window_position">center</property>
    <property name="default_width">440</property>
    <property name="default_height">250</property>
    <child>
      <object class="GtkLabel" id="label1">
        <property name="visible">True</property>
        <property name="label" translatable="yes">Hello world</property>
      </object>
    </child>
  </object>
</interface>

He buscado de que es el error pero no encuentro nada