code: def msg(self, msg_type, content):
      return self.session.msg(msg_type, content)
  
imports: import copy
  import json
  from unittest import TestCase
  from jupyter_client.adapter import V4toV5, adapt, code_to_line
  from jupyter_client.session import Session
label_desc: Use image node_id 1 for calling the V5toV4TestCase obj's underlying member method code with example usage: obj.msg(msg_type, content) and returns: self