def METHOD_NAME():
    args = parse_args()
    urls = find_snapshot_urls(args.directory)
    snapshots = None
    if args.cache:
        try:
            with open(args.cache, encoding="utf8") as f:
                snapshots = json.load(f)
        except:
            print(f"No snapshots cache found at {args.cache}")
            sys.exit(1)
    else:
        snapshots = fetch_snapshots_api(args.url, args.timeout)
        if not snapshots:
            print(f"Cannot download snapshots from {args.url}")
            sys.exit(1)
    return check_snapshot_urls(urls, snapshots, errors_only=args.errors_only)