public function getTwitterAccessToken()
    {
        $consumer_key    = urlencode($this->args['api_user']);
        $consumer_secret = urlencode($this->args['api_secret']);

        // Concatenate key and secret and base64 encode
        $bearer_token = $consumer_key . ':' . $consumer_secret;
        $base64_bearer_token = base64_encode($bearer_token);

        // Request access token
        $endpoint = 'https://api.twitter.com/oauth2/token';

        // Request headers
        $headers = array(
            "POST /oauth2/token HTTP/1.1",
            "Host: api.twitter.com",
            "User-Agent: jonhurlock Twitter Application-only OAuth App v.1",
            "Authorization: Basic " . $base64_bearer_token,
            "Content-Type: application/x-www-form-urlencoded;charset=UTF-8"
        );

        // Postdata
        $data = array(
            'grant_type' => 'client_credentials'
        );

        // Curl and format response
        $curl = new \Modularity\Helper\Curl();
        $response = $curl->request('POST', $endpoint, $data, null, $headers);
        $response = json_decode($response);

        if (isset($response->errors)) {
            return $response;
        }

        return $response->access_token;
    }