docs: def _bash_completion(self):
          """Prints all of the commands and options for bash-completion."""
          commands = set()
          options = set()
          for option, _action in self.parser._option_string_actions.items():
              options.add(option)
          for _name, _command in self.command_manager:
              commands.add(_name)
              cmd_factory = _command.load()
              cmd = cmd_factory(self, None)
              cmd_parser = cmd.get_parser('')
              for option, _action in cmd_parser._option_string_actions.items():
                  options.add(option)
          print(' '.join(commands | options))