/**
  * Expires in-memory cache for eZContentClass.
  *
  * Clears cache for fetched eZContentClass objects,
  * class identifiers and class attributes.
  *
  * @since 4.2
  */
 public static function expireCache()
 {
     unset($GLOBALS['eZContentClassObjectCache']);
     self::$identifierHash = null;
     eZContentClassAttribute::expireCache();
 }