code: def until_not_synced(self, timeout=None):
          
          not_synced_states = [state for state in self._state.valid_states
                               if state != 'synced']
          not_synced_futures = [self._state.until_state(state)
                                for state in not_synced_states]
          return until_any(*not_synced_futures, timeout=timeout)
docs: Convenience method to wait (with Future) until client is not synced