protected function createNexmoDriver()
    {
        return new Channels\NexmoSmsChannel(
            new NexmoClient(new NexmoCredentials(
                $this->app['config']['services.nexmo.key'],
                $this->app['config']['services.nexmo.secret']
            )),
            $this->app['config']['services.nexmo.sms_from']
        );
    }