public function filterByKeys(array $keys)
    {
        /** @noinspection PhpMethodParametersCountMismatchInspection */
        $newInstance = new self();
        $newInstance->setArray(array_filter($this->array, function ($key) use ($keys) {
            return array_search($key, $keys) !== false;
        }, ARRAY_FILTER_USE_KEY));
        return $newInstance;
    }