def METHOD_NAME(privkey_data: List[str]) -> Tuple[int, List[bytes]]:
    privkeys = []
    sigmask = 0
    for key in privkey_data:
        try:
            idx, key_hex = key.split(":", maxsplit=1)
            privkeys.append(bytes.fromhex(key_hex))
            sigmask |= 1 << (int(idx) - 1)
        except ValueError:
            click.echo(f"Could not parse key: {key}")
            click.echo("Keys must be in the format: <key index>:<hex-encoded key>")
            raise click.ClickException("Unrecognized key format.")
    return sigmask, privkeys