src/Page/CartPageController.php
public function CartForm()
    {
        $cart = $this->Cart();
        if (!$cart) {
            return false;
        }
        $form = CartForm::create($this, 'CartForm', $cart);

        $this->extend('updateCartForm', $form);

        return $form;
    }
public function CartForm()
    {
        $cart = $this->Cart();
        if (!$cart) {
            return false;
        }
        $form = CartForm::create($this, 'CartForm', $cart);

        $this->extend('updateCartForm', $form);

        return $form;
    }
A form for updating cart items