A PHP Error was encountered

Severity: Notice

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

Filename: models/ModelCart.php

Line Number: 15

Backtrace:

File: /home/mitraja5/public_html/application/models/ModelCart.php
Line: 15
Function: _error_handler

File: /home/mitraja5/public_html/application/controllers/Cart.php
Line: 19
Function: get_cartbyidcustomer

File: /home/mitraja5/public_html/index.php
Line: 315
Function: require_once