class KeyUpdateCommand implements Callable<CliResult> {

    List<char[]> passwords() throws IOException {
        if (password != null) {
            return singletonList(password.toCharArray());
        } else if (passwordFile != null) {
            return Files.readAllLines(passwordFile).stream().map(String::toCharArray).collect(Collectors.toList());
        } else {
            return emptyList();
        }
    }

      KeyUpdateCommand(KeyEncryptorFactory keyEncryptorFactory, PasswordReader passwordReader);

}