docs: def file_upload(f):
      """
      Return list of `werkzeug.datastructures.FileStorage` objects - files to be
      uploaded
      """
  
      @wraps(f)
      def file_upload_decorator(*args, **kwargs):
          # If the data is already transformed, we do not transform it any
          # further.
          task_data = _get_data_from_args(args)
  
          if task_data is None:
              logging.error("Task data is empty during FilesUploadDecorator.")
  
          task_data.transform_payload(lambda _: request.files.getlist('file'))
          return f(*args, **kwargs)
  
      return file_upload_decorator