class Emailer {

    public static Optional<Emailer> firstFromMailboxList(MailboxList list) {
        return Optional.ofNullable(list)
            .flatMap(mailboxes -> mailboxes.stream()
                .map(Emailer::fromMailbox)
                .findFirst());
    }

    @VisibleForTesting  Emailer(Optional<String> name, Optional<String> email);

}