code: def FinalizeTaskStorage(self, task):
      
      if task.identifier not in self._task_storage_writers:
        raise IOError('Storage writer for task: {0:s} does not exist.'.format(
            task.identifier))
docs: Finalizes a processed task storage.
  
      Args:
        task (Task): task.
  
      Raises:
        IOError: if the task storage does not exist.
        OSError: if the task storage does not exist.