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]

def _get_ancestors(self, current=None):
        """
        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]
        """
        if not current:
            current = []
        current.insert(0, self)
        if self.is_root:
            if current:
                return current
        else:
            return self.parent._get_ancestors(current)