Create parent command object in cmd tree then return
        the last parent command object.
        :rtype: dict

def add_parent_commands(self, cmd_path, help=None):
        """
        Create parent command object in cmd tree then return
        the last parent command object.
        :rtype: dict
        """
        existed_cmd_end_index = self.index_in_tree(cmd_path)
        new_path, existed_path = self._get_paths(
            cmd_path,
            existed_cmd_end_index,
        )
        parent_node = self.get_cmd_by_path(existed_path)

        last_one_index = 1
        new_path_len = len(new_path)
        _kwargs = {}
        for cmd_name in new_path:
            if last_one_index >= new_path_len:
                _kwargs['help'] = help
            sub_cmd = parent_node['cmd'].add_cmd(
                cmd_name, **_kwargs
            )
            parent_node = _mk_cmd_node(cmd_name, sub_cmd)
            self._add_node(
                parent_node,
                existed_path + new_path[:new_path.index(cmd_name)]
            )
            last_one_index += 1
        return parent_node