code: def close_files(self):
          
          if self._events is not None:
              self._events.close()
              self._events = None
          if self._history is not None:
              self._history.close()
              self._history = None
docs: Close open files to avoid Python warnings on termination:
  
          Exception ignored in: <_io.FileIO name='wandb/dryrun-20180130_144602-9vmqjhgy/wandb-history.jsonl' mode='wb' closefd=True>
          ResourceWarning: unclosed file <_io.TextIOWrapper name='wandb/dryrun-20180130_144602-9vmqjhgy/wandb-history.jsonl' mode='w' encoding='UTF-8'>