protected function fetchObjectFromCache($key)
 {
     $object = $this->collection->findOne(['_id' => $key]);
     if ($object && isset($object->data)) {
         $item = new CacheItem($key, true, unserialize($object->data));
         if (isset($object->expiresAt)) {
             $item->expiresAt($object->expiresAt->toDateTime());
         }
         return $item;
     }
     return false;
 }