prepareEsdSerialsAssociation example

if (!is_writable($esdDir)) {
                    throw new RuntimeException(sprintf('Unable to save ESD-file, as the directory "%s" is not writable.', $esdDir));
                }

                copy($file, $saveFile);
                @unlink($file);
                $data['esd']['file'] = $saveFileName;
            }

            if (isset($data['esd']['serials'])) {
                $data = $this->prepareEsdSerialsAssociation($data, $esd);
            }

            $esd->fromArray($data['esd']);
            $variant->setEsd($esd);
        } elseif ($data['esd'] === null) {
            $variant->setEsd(null);
        }

        unset($data['esd']);

        return $data;
    }