def __init__(self, name, filename=None):
        self.name = name
        super(NamedRequirements, self).__init__(filename=filename)
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)