Hi guys I´m new in the PHP SDK API from Facebook, now I have some troubles with a simple GET query here it´s my controller's code: 

```
<?php

defined('BASEPATH') or exit('No direct script access allowed');

class Facebook extends CI_Controller
{
    public $app_id = 'XXXXXXXX';
    public $app_secret = 'XXXXXXXXXX';

    public function __construct()
    {
        parent::__construct();
        $this->load->library('FacebookSDK');
    }

    public function index()
    {
        $fb = new Facebook\Facebook(array(
            'app_id' => $this->app_id,
            'app_secret' => $this->app_secret,
            'default_graph_version' => 'v2.10',
        ));

        $helper = $fb->getRedirectLoginHelper();
        $accessToken = $helper->getAccessToken();

        try {
            $request = $fb->get('/me/events', $accessToken);
            $eventos = $request->getGraphObject()->asArray();
            $datos['eventos'] = $eventos;
            $this->load->view(home, $datos);
            /* handle the result */
        } catch (Facebook\Exceptions\FacebookResponseException $e) {
            // When Graph returns an error
            echo 'Graph returned an error: '.$e->getMessage();
        } catch (Facebook\Exceptions\FacebookSDKException $e) {
            // When validation fails or other local issues
            echo 'Facebook SDK returned an error: '.$e->getMessage();
        }
    }
}

```

The error throws me "Facebook SDK returned an error: You must provide an access token."
PD: I´m working with Codeigniter