MissingSystemTranslationException example

        // the validation is only required for new entities         if ($existence->exists()) {
            return;
        }

        $languageIds = array_keys($value);
        // the translation in the system language is always required for new entities,         // if there is at least one required translated field         if ($referenceDefinition->hasRequiredField() && !\in_array(Defaults::LANGUAGE_SYSTEM, $languageIds, true)) {
            throw new MissingSystemTranslationException($path . '/' . Defaults::LANGUAGE_SYSTEM);
        }

        yield from [];
    }
}