Filters not working in CodeIgniter 4

PHP Code:

filter
use Modules\Login\Filters\Auth;
use Modules\Login\Filters\Noauth;

public $aliases = [
"auth"    => Auth::class,
"noauth"    => Noauth::class,
];

Auth
public function before(RequestInterface $request, $arguments = null)
{
    if (!session()->get('isAdminLoggedIn')) {
        return redirect()->to(base_url(route_to('admin')));
    }
}

Route
$routes->get("dashboard", "DashboardController::index", ["filter" => "auth"]); 


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What is the issue in above code. Filter is not working in CodeIgniter 4. Not working filter auth in dashboard route.