Edit file File name : NumberGeneratorInterface.php Content :<?php /* * This file is part of the Kimai time-tracking app. * * For the full copyright and license information, please view the LICENSE * file that was distributed with this source code. */ namespace App\Invoice; /** * Class NumberGeneratorInterface defines all methods that invoice number generator have to implement. */ interface NumberGeneratorInterface { /** * @param InvoiceModel $model */ public function setModel(InvoiceModel $model); /** * @return string */ public function getInvoiceNumber(): string; /** * Returns the unique ID of this number generator. * * Prefix it with your company name followed by a hyphen (e.g. "acme-"), * if this is a third-party generator. * * @return string */ public function getId(): string; } Save