docs: def get_results_generator(future_list, timeout=None, sort_by_completed=False):
      """Return as a generator of tasks order by completed sequence."""
      try:
          # python2 not support yield from
          if sort_by_completed:
              for future in as_completed(future_list, timeout=timeout):
                  yield future.x
          else:
              for future in future_list:
                  yield future.x
      except TimeoutError:
          return