$user = Loader::model("User"); 报异常解决方法
视频代码：
use think\Loader;
$user = Loader::model("User");
$res = $user::get(3);
$res = $res->toArray();
dump($res);
5.1以后修改为
use think\facade\App;
$user = App::model("User");
$res = $user::get(3);
$res = $res->toArray();
dump($res);
