get_instance function

For session in file.

PHP Code:

<?= session('item'); ?>

It is also chainable.

PHP Code:

<?php

$session = session();

$tmp = session()->item;
$tmp = session()->get('item');

?>

Very easy with CodeIgniter 4.

In this case is session() a function that does not exist. Don't I have to load the session driver first? With Codeigniter 3 it was done this way

Code:

$CI =& get_instance();
$CI->load->driver('session');

How should that be done with CodeIgniter 4?