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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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