WC_Cart::get_cart_item_quantities PHP Method

    public function get_cart_item_quantities()
    {
        $quantities = array();
        foreach ($this->get_cart() as $cart_item_key => $values) {
            $product = $values['data'];
            $quantities[$product->get_stock_managed_by_id()] = isset($quantities[$product->get_stock_managed_by_id()]) ? $quantities[$product->get_stock_managed_by_id()] + $values['quantity'] : $values['quantity'];
        }
        return $quantities;
    }