def METHOD_NAME(self):
    self.dialog = Gtk.MessageDialog(self.parent,
            0, 0, Gtk.ButtonsType.CANCEL, self.subtitle or self.title)
    self.dialog.set_modal(True)
    self.dialog.connect('delete-event', self._on_delete_event)
    if self.cancellable:
        def cancel_callback(dialog, response):
            self.cancellable = False
            self.cancelled = True
            self.dialog.set_deletable(False)
            self.dialog.set_response_sensitive(Gtk.ResponseType.CANCEL, False)
            if callable(self.cancel_callback):
                self.cancel_callback(dialog, response)
        self.cancel_id = self.dialog.connect('response', cancel_callback)
    self.dialog.set_title(self.title)
    self.dialog.set_deletable(self.cancellable)
    # Avoid selectable text (requires PyGTK >= 2.22)
    if hasattr(self.dialog, 'get_message_area'):
        for label in self.dialog.get_message_area():
            if isinstance(label, Gtk.Label):
                label.set_selectable(False)
    self.dialog.set_response_sensitive(Gtk.ResponseType.CANCEL, self.cancellable)
    self.progressbar = Gtk.ProgressBar()
    self.progressbar.set_show_text(True)
    self.progressbar.set_ellipsize(Pango.EllipsizeMode.END)
    # If the window is shown after the first update, set the progress
    # info so that when the window appears, data is there already
    if self._initial_progress is not None:
        self.progressbar.set_fraction(self._initial_progress)
    if self._initial_message is not None:
        self.progressbar.set_text(self._initial_message)
    self.dialog.vbox.add(self.progressbar)
    self.indicator = SpinningProgressIndicator()
    self.dialog.set_image(self.indicator)
    self.dialog.show_all()
    self._update_gui()
    # previous self.source_id timeout is removed when this returns False
    # use timeout_add, not util.idle_timeout_add, so it updates before Gtk+ redraws the dialog
    self.source_id = GLib.timeout_add(self.INTERVAL, self._update_gui)
    return False