A PHP Error was encountered

Severity: Notice

Message: Trying to access array offset on value of type null

Filename: libraries/Cart.php

Line Number: 442

Backtrace:

File: /home/jrink/levin-shop.com/public_html/application/views/cart/index.php
Line: 1
Function: total_items

File: /home/jrink/levin-shop.com/public_html/application/views/layout/default.php
Line: 36
Function: view

File: /home/jrink/levin-shop.com/public_html/application/controllers/Cart.php
Line: 53
Function: view

File: /home/jrink/levin-shop.com/public_html/index.php
Line: 308
Function: require_once