public function lookupByKeys($collectionId, array $keys, array $options = [])
    {
        $_documentClass = $this->_documentClass;

        $body = [
            self::OPTION_COLLECTION => $collectionId,
            self::OPTION_KEYS       => $keys
        ];

        $response = $this->getConnection()->put(Urls::URL_LOOKUP_BY_KEYS, $this->json_encode_wrapper($body));

        $responseArray = $response->getJson();

        $result = [];
        foreach ($responseArray['documents'] as $document) {
            $result[] = $_documentClass::createFromArray($document, $options);
        }

        return $result;
    }