laravel config配置文件要如何才能调用setting函数

安装了一个settting功能
但是在config/easysms.php中无法正常调用

class Sender {

    public static function send($phone, Message $message, array $config = []) {

        if(empty($config))
        {
            $config = [
                // HTTP 请求的超时时间（秒）
                'timeout' => 10.0,

                // 默认发送配置
                'default' => [
                    // 网关调用策略，默认：顺序调用
                    'strategy' => \Overtrue\EasySms\Strategies\OrderStrategy::class,

                    // 默认可用的发送网关
                    'gateways' => [
                        'aliyun', 'smsbao'
                    ],
                ],
                // 可用的网关配置
                'gateways' => [
                    'errorlog' => [
                        'file' => '/tmp/easy-sms.log',
                    ],
                    'smsbao' => [
                        'user' => setting('smsbao_username'),
                        'password' => setting('smsbao_password')
                    ],
                    'aliyun' => [
                        'access_key_id' => setting('sms_aliyun_access_key_id'),
                        'access_key_secret' => setting('sms_aliyun_access_key_secret'),
                        'sign_name' => setting('sms_aliyun_sign_name'),
                    ],
                ],
            ];
        }

        $sms = new EasySms($config);
        try {
            return $sms->send($phone, $message);
        } catch (NoGatewayAvailableException $exception) {
            throw $exception;
        }
    }
}