private function getUpdatedLanguageCodes(APIContentUpdateStruct $contentUpdateStruct)
    {
        $languageCodes = [
            $contentUpdateStruct->initialLanguageCode => true,
        ];

        foreach ($contentUpdateStruct->fields as $field) {
            if ($field->languageCode === null || isset($languageCodes[$field->languageCode])) {
                continue;
            }

            $languageCodes[$field->languageCode] = true;
        }

        return array_keys($languageCodes);
    }