def save(self, doc):
        if doc.id:
            return self.update(doc)
        else:
            return self.insert(doc)
def _setup_drag(self, item):
    self._drag_and_drop_context.setup_drag(
      item.item_widget,
      self._get_drag_data,
      self._on_drag_data_received,
      [item],
      [item],
      self)