protected function formatOne($transUnit)
    {
        if (is_object($transUnit)) {
            $transUnit = $this->toArray($transUnit);
        } elseif (StorageInterface::STORAGE_MONGODB == $this->storage) {
            $transUnit['id'] = $transUnit['_id']->{'$id'};
        }

        $formatted = array(
            '_id'     => $transUnit['id'],
            '_domain' => $transUnit['domain'],
            '_key'    => $transUnit['key'],
        );

        // add locales in the same order as in managed_locales param
        foreach ($this->localeManager->getLocales() as $locale) {
            $formatted[$locale] = '';
        }

        // then fill locales value
        foreach ($transUnit['translations'] as $translation) {
            if (in_array($translation['locale'], $this->localeManager->getLocales())) {
                $formatted[$translation['locale']] = $translation['content'];
            }
        }

        return $formatted;
    }