def save(self):
        tmp_path = self.path + '.tmp'
        with open(tmp_path, 'w') as f:
            f.write(json.dumps(self.body_labels.items()))
        os.rename(tmp_path, self.path)
def _rename_item_names(self, start_index):
    for index, item in enumerate(self._items[start_index:]):
      item.label.set_label(self._get_item_name(index + 1 + start_index))