code: def add_status_code(code):
      
      def class_decorator(cls):
          """内部装饰函数,用于将异常类注册到对应的状态码.
  
          Parameters:
              cls (Callable): - 要注册的异常类
          Return:
              (Callable): - 注册的异常类
  
          """
          cls.status_code = code
          _mprpc_exceptions[code] = cls
          return cls
  
      return class_decorator
docs: 用于将mprpc的标准异常注册到`_mprpc_exceptions`的装饰器.
  
      Parameters:
          code (int): - 标准状态码
      Return:
          (Callable): - 装饰函数