phorge-phorge/src/applications/releeph/mail/ReleephRequestReplyHandler.php

<?php

final class ReleephRequestReplyHandler
  extends PhabricatorApplicationTransactionReplyHandler {

  public function validateMailReceiver($mail_receiver) {
    if (!($mail_receiver instanceof ReleephRequest)) {
      throw new Exception('Mail receiver is not a ReleephRequest!');
    }
  }

  public function getObjectPrefix() {
    return 'Y';
  }

}