用递归生成科目级别

先将科目的每一级别保存到列表中,然后根据选择的打印级别,就可以找到相对应的科目级别

    def parse_account_code(self, num, accounts, res):
        res.append(accounts)
        accounts = accounts.parent_id
        if not accounts.parent_id:
            res.append(accounts)
            if len(res) > num:
                return res[::-1][num-1].code
            else:
                return res[::-1][-1].code
        return self.parse_account_code(num, accounts, res)