* identify objects used to build the cache item, which should trigger
* cache invalidation when updated. For example if a cached item represents
* a node, both the node ID and the author's user ID might be passed in as
- * tags. For example array('node' => array(123), 'user' => array(92)).
+ * tags. For example ['node:123', 'node:456', 'user:789'].
*
* @see \Drupal\Core\Cache\CacheBackendInterface::get()
* @see \Drupal\Core\Cache\CacheBackendInterface::getMultiple()