Php 使用Symfony 3发送一个信号推送通知

我用Ionic 3创建了一个移动应用程序，我想通过一个信号在Symfony 3中发送通知

我阅读了一个信号的文档和此文档：

我在Symfony中创建了一个服务，但是我被阻止了，我不知道该放什么

$guzzle = new GuzzleClient([
                            // ..config
                           ]);

我的服务：

<?php

namespace SGBundle\Service\OneSignal;

use GuzzleHttp\Client as GuzzleClient;
use Http\Adapter\Guzzle5\Client as GuzzleAdapter;
use Http\Client\Common\HttpMethodsClient as HttpClient;
use Http\Message\MessageFactory\GuzzleMessageFactory;
use OneSignal\Config;
use OneSignal\Devices;
use OneSignal\OneSignal;
use SGBundle\Controller\BaseController;

/**
 * Class OneSignalService
 *
 * @package SGBundle\Service\OneSignal
 */
class OneSignalService extends BaseController
{
    /**
     * @return mixed
     */
    public function sendMessage()
    {
        $config = new Config();
        $config->setApplicationId('xxx');
        $config->setApplicationAuthKey('xx');
        $config->setUserAuthKey('xxx');

        $guzzle = new GuzzleClient([
                                       // ..config
                                   ]);

        $client = new HttpClient(new GuzzleAdapter($guzzle), new GuzzleMessageFactory());
        $api = new OneSignal($config, $client);

    }

---

没人帮我吗？：/