code: def is_return_code_zero(args):
      """Return true iff the given command's return code is zero.
  
      All the messages to stdout or stderr are suppressed.
      """
      with open(os.devnull, "wb") as FNULL:
          try:
              subprocess.check_call(args, stdout=FNULL, stderr=FNULL)
          except subprocess.CalledProcessError:
              # The given command returned an error
              return False
          except OSError:
              # The given command was not found
              return False
          return True
  
label_desc: Use image node_id 1 for calling a global function with example usage: is_return_code_zero(args) and returns: True, False, False