getFreeSerialCount example

$esd = $this->get('models')->getRepository(Esd::class)->find($esdId);
        if (!$esd) {
            $this->View()->assign([
                'success' => false,
                'message' => sprintf('ESD by id %s not found', $esdId),
            ]);

            return;
        }

        $freeSerialsCount = $this->getFreeSerialCount($esdId);
        $variant = $esd->getArticleDetail();
        $variant->setInStock($freeSerialsCount);

        $esd->fromArray($this->Request()->getPost());
        $this->getManager()->flush();

        $this->View()->assign([
            'data' => $this->Request()->getPost(),
            'success' => true,
        ]);
    }