class_docstr: Convert msg spec V4 to V5
class_docstr_tok: ["Convert","msg","spec","V4","to","V5"]
code: def complete_request(self, msg):
      old_content = msg["content"]
  
      new_content = msg["content"] = {}
      new_content["code"] = old_content["line"]
      new_content["cursor_pos"] = old_content["cursor_pos"]
      return msg
  
imports: import re
  import json
  from jupyter_client import protocol_version_info
label_desc: Use image node_id 5 for calling the V4toV5 obj's underlying member method code with example usage: obj.complete_request(msg) and returns: msg