code: def _get_ancestors(self, current=None):
          
          if not current:
              current = []
          current.insert(0, self)
          if self.is_root:
              if current:
                  return current
          else:
              return self.parent._get_ancestors(current)
docs: Gets the ancestors of this node
          :param current: The current ancestor list
          :return: The ancestor list
          :type current: list[Plate] | list[str] | list[unicode] | None
          :rtype: list[Plate] | list[str] | list[unicode]