Edit file File name : DuplicateInvoiceNumberException.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; final class DuplicateInvoiceNumberException extends \Exception { public function __construct(string $invoiceNumber) { parent::__construct('Invoice number "' . $invoiceNumber . '" already existing'); } } Save