code: def copy_submission_locally(self, cloud_path):
      
      local_path = os.path.join(self.download_dir, os.path.basename(cloud_path))
      cmd = ['gsutil', 'cp', cloud_path, local_path]
      if subprocess.call(cmd) != 0:
        logging.error('Can\'t copy submission locally')
        return None
      return local_path
docs: Copies submission from Google Cloud Storage to local directory.
  
      Args:
        cloud_path: path of the submission in Google Cloud Storage
  
      Returns:
        name of the local file where submission is copied to