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_event_box_leave_notify_event(self, event_box, event):
    if event.detail != gtk.gdk.NOTIFY_INFERIOR:
      self._hbox_buttons.hide()