Wraps the Cache Service for Spi cache to apply key prefix for the cache
 /**
  * Clear all user persistence cache.
  *
  * @param int|null $id Purges all users cache if null
  * @throws \eZ\Publish\Core\Base\Exceptions\InvalidArgumentType On invalid $id type
  */
 public function user($id = null)
 {
     if ($this->allCleared === true || $this->isSwitchedOff()) {
         return;
     }
     if ($id === null) {
         $this->cache->clear('user');
     } elseif (is_scalar($id)) {
         $this->cache->clear('user', $id);
     } else {
         throw new InvalidArgumentType('$id', 'int|null', $id);
     }
 }
 /**
  * Clear all user persistence cache
  *
  * @param int|null $id Purges all users cache if null
  * @throws \eZ\Publish\Core\Base\Exceptions\InvalidArgumentType On invalid $id type
  */
 public function user($id = null)
 {
     if ($this->allCleared === true || $this->enabled === false) {
         return;
     }
     if ($id === null) {
         $this->cache->clear('user');
     } else {
         if (is_scalar($id)) {
             $this->cache->clear('user', $id);
         } else {
             throw new InvalidArgumentType("\$id", "int|null", $id);
         }
     }
 }