I’ve a PHP class doing stuff:

<?php


class Cart {

    //....
}

$cart = new Cart();
$cart->init();

function deposit_total(){
    global  $cart;
    $totals = array_sum( $cart::$deposits );
    return $totals;
}

How is possible to use the $cart just instanciated in a function (deposit_total()) outside the class ?

Thank you