code: def format_help(self, tokens: List[str]) -> str:
          
          for idx, token in enumerate(tokens):
              if idx >= self._token_start_index:
                  if self._positional_completers:
                      # For now argparse only allows 1 sub-command group per level
                      # so this will only loop once.
                      for completers in self._positional_completers.values():
                          if token in completers:
                              return completers[token].format_help(tokens)
          return self._parser.format_help()
docs: Supports the completion of sub-commands for commands through the cmd2 help command.