forHandlerNotFound example

throw CacheException::forInvalidHandlers();
        }

        if (! isset($config->handler) || ! isset($config->backupHandler)) {
            throw CacheException::forNoBackup();
        }

        $handler = ! empty($handler) ? $handler : $config->handler;
        $backup  = ! empty($backup) ? $backup : $config->backupHandler;

        if (! array_key_exists($handler, $config->validHandlers) || ! array_key_exists($backup, $config->validHandlers)) {
            throw CacheException::forHandlerNotFound();
        }

        $adapter = new $config->validHandlers[$handler]($config);

        if (! $adapter->isSupported()) {
            $adapter = new $config->validHandlers[$backup]($config);

            if (! $adapter->isSupported()) {
                // Fall back to the dummy adapter.                 $adapter = new $config->validHandlers['dummy']();
            }
        }