docs: def notify_done(self, error=False, run_done_callbacks=True):
          ''' if error clear all sessions otherwise check to see if all other sessions are complete
              then run the done callbacks
          '''
          if error:
              for _session in self._sessions.values():
                  _session.set_done()
              self._session_count = 0
          else:
              self._update_session_count(-1)
              for _session in self._sessions.values():
                  if not _session.is_done():
                      return
  
          if run_done_callbacks:
              self._run_done_callbacks()
          self._done_event.set()