Notice: Undefined variable: session in C:\xampp\htdocs\tienda\app\view\main\index.php on line 14

Fatal error: Uncaught Error: Call to a member function customer() on null in C:\xampp\htdocs\tienda\app\view\main\index.php:14 Stack trace: #0 {main} thrown in C:\xampp\htdocs\tienda\app\view\main\index.php on line 14