static function expireCache( $expireCluster = true )
    {
        unset( $GLOBALS['eZContentLanguageList'],
               $GLOBALS['eZContentLanguagePrioritizedLanguages'],
               $GLOBALS['eZContentLanguageMask'],
               $GLOBALS['eZContentLanguageCronjobMode'] );

        // With the solution to #14227 we also need to clear the cached
        // list of languages
        if ( $expireCluster )
        {
            $cachePath = eZSys::cacheDirectory() . '/ezcontentlanguage_cache.php';
            eZClusterFileHandler::instance()->fileDelete( $cachePath );
        }
    }