def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def _on_item_widget_key_press_event(self, widget, event, item):
    if event.state & gtk.gdk.MOD1_MASK:     # Alt key
      key_name = gtk.gdk.keyval_name(event.keyval)
      if key_name in ["Up", "KP_Up"]:
        self.reorder_item(
          item, self._get_item_position(item) - 1)
      elif key_name in ["Down", "KP_Down"]:
        self.reorder_item(
          item, self._get_item_position(item) + 1)