class_docstr: Produce a custom-formatted `--help` option.
  
  See https://goo.gl/DKtHb5 for details.
class_docstr_tok: ["Produce","a","custom-formatted","`","--","help","`","option",".","See","https",":","\/\/goo.gl\/DKtHb5","for","details","."]
code: def _format_action_invocation(self, action):
      # used to suppress one utterance in the super parser.
      if isinstance(action, argparse._SubParsersAction):
          return ""
      if not action.option_strings or action.nargs == 0:
          return super()._format_action_invocation(action)
      default = self._get_default_metavar_for_optional(action)
      args_string = self._format_args(action, default)
      return ", ".join(action.option_strings) + " " + args_string
  
imports: import argparse
  import importlib
  import os
  import sys
  import datetime
  import parlai
  import parlai.utils.logging
  from parlai.core.build_data import modelzoo_path
  from parlai.core.loader import load_teacher_module, load_agent_module, load_world_module
  from parlai.tasks.tasks import ids_to_tasks
  from parlai.core.opt import Opt
  from parlai.utils.io import PathManager
  from typing import List, Optional
label_desc: Use image node_id 4 for calling the CustomHelpFormatter obj's underlying member method code with example usage: obj._format_action_invocation(action) and returns: unknown, str, super