sopify-test-modul-fo/Core/FacturisRepository/ProformaRepository.php

<?php 

namespace Core\FacturisRepository;

class ProformaRepository 
extends Repository
implements \Core\App\Repository\Facturis\ProformaInterface
{
    public function add($proforma)
    {
        $response = $this->insertProforma($proforma);
    }

}