title: How to use Gtk.Widget.set_template()
body: <p>I am trying to use the <code>Gtk.Widget.set_template()</code> method but I am not sure how to use it <em>without</em> Gio.Resource. I am using python3 with gi.repository.</p>
  
  <p>Let's say I have a foowidget.ui and then I would like to have a class:</p>
  
  <pre><code>class FooWidget(Gtk.Box):
      Gtk.Box.__init__(self)
      #set_template here with 'foowidget.ui'
      self.init_template()
  </code></pre>