docs: def iter_walk_menus(self):
          """
          Useful for example to spread changes to the prompt, e.g. enabling or
          disabling colors.
          """
          yield self
          for item in self.name_to_command.values():
              if isinstance(item, _Menu):
                  # "Generator delegation" ;)
                  # https://docs.python.org/3/whatsnew/3.3.html#pep-380
                  yield from item.iter_walk_menus()