def remove_expired_multipartobjects():
    """Remove expired multipart objects."""
    delta = current_app.config['FILES_REST_MULTIPART_EXPIRES']
    expired_dt = datetime.utcnow() - delta

    file_ids = []
    for mp in MultipartObject.query_expired(expired_dt):
        file_ids.append(str(mp.file_id))
        mp.delete()

    for fid in file_ids:
        remove_file_data.delay(fid)