thinkphp 如何使用内置的验证码规则验证

namespace app\index\validate;

use think\Validate;

class User extends Validate
{
    protected $rule = [
        ‘ceshi‘=>[‘require‘,‘captcha‘]
    ];

    protected $message = [
  
    ];

    protected $scene = [
        ‘edit‘ => [‘ceshi‘],
    ];
}

//验证码图片测试
    public function tp(Request $request)
    {
        $data = $request->post();

        $result = $this->validate($data, "User.edit");
           
        dump($result);
    }