def normalize(body_part_tup,):
    return '\n\n'.join(
        [
            '{}\n\n{}'.format(
                str(p.headers[b'Content-Disposition'], p.encoding), p.text
            )
            for p in sorted(
                body_part_tup, key=lambda p: p.headers[b'Content-Disposition']
            )
        ]
    )