Librarie File & SplFileInfo Namespace Error

Hi,
I am trying to read a CSV file with the Class 'File' but ran in some errors.

PHP Code:

$file = "test.csv";
$objFileCsv = new \CodeIgniter\Files\File($file);
echo $objFileCsv->getMTime();
$splFileCsv = $objFileCsv->openFile('r');
 $splFileCsv->setFlags(SplFileObject::READ_CSV); 


This i tryed in a helper without namespace and there is no problem. But in a Controller there is a error.

Class "App\Controllers\SplFileObject" not found

I didn't get it. I know its because the Namespace but SplFileInfo is a PHP build in Class and the Scope should be global or?

I also try

PHP Code:

namespace App\Controllers;
use SplFileInfo; 


What i am missing?

Use  \SplFileObject

Simple CI 4 project for beginners codeigniter-expenses ( topic )

Use  \SplFileObject

Thank you. Problem solved