def save(self, doc):
        if doc.id:
            return self.update(doc)
        else:
            return self.insert(doc)
def remove_item(self, item):
    item_position = self._get_item_position(item)
    if item_position < len(self._items) - 1:
      next_item_position = item_position + 1
      self._items[next_item_position].item_widget.grab_focus()