docs: def handle_error(self, e):
          """
          Resolve the problem about sometimes error message specified by programmer won't output to user.
  
          Flask-RESTFul's error handler handling format different exceptions has different behavior.
          If we raise an normal Exception, it will raise it again.
  
          If we report error by `restful.abort()`,
           likes `restful.abort(400, message="my_msg", custom_data="value")`,
           it will make a response like this:
  
              Status     400
              Content    {"message": "my_msg", "custom_data": "value"}
  
          The error message we specified was outputted.
  
          And if we raise an HTTPException,
              likes `from werkzeug.exceptions import BadRequest; raise BadRequest('my_msg')`,
              if will make a response too, but the error message specified by ourselves was lost:
  
              Status     400
              Content    {"status": 400, "message": "Bad Request"}
  
          The reason is, flask-restful always use the `data` attribute of HTTPException to generate response content.
          But, standard HTTPException object didn't has this attribute.
          So, we use this method to add it manually.
  
  
          Some reference material:
  
          Structure of exceptions raised by restful.abort():
              code: status code
              description: predefined error message for this status code
              data: ｛
              　　　　message: error message
              ｝
  
          Structure of python2's standard Exception:
              message: error message
          Exceptions in python3 didn't has hte `message` attribute, but use `str(exception)` can get it's message.
  
          Structure of standard `werkzeug.exceptions.HTTPException` (same as BadRequest):
              code: status code
              name: the name correspondence to status code
              description: error message
          """
          if isinstance(e, HTTPException) and not hasattr(e, 'data'):
              e.data = dict(message=e.description)
          return super(ErrorHandledApi, self).handle_error(e)