protected static function initialise_cachestore_instances(array $stores, cache_definition $definition) {
        $return = array();
        $factory = cache_factory::instance();
        foreach ($stores as $name => $details) {
            $store = $factory->create_store_from_config($name, $details, $definition);
            if ($store !== false) {
                $return[] = $store;
            }
        }
        return $return;
    }