code: def __str__(self):
      return self.msg
  
imports: import logging
  import os
  import subprocess
  import time
  from guild import config
  from guild import exit_code
  from guild import log
  from guild import op_dep
  from guild import op_util
  from guild import run
  from guild import util
label_desc: Use image node_id 2 for calling the InvalidOpDef obj's underlying member method code with example usage: obj.__str__() and returns: self