private function validateSearchClients(array $clients)
    {
        foreach ($clients as $name => $config) {
            $this->validateTypeAndService($config, sprintf('as3_modlr.search_clients.%s', $name));
            switch ($config['type']) {
                case 'elastic':
                    $this->validateLibClassExists('Search\Elastic\Client', sprintf('as3_modlr.search_clients.%s.type', $name));
                    break;
                default:
                    break;
            }
        }
    }