public function __construct($carro)
 {
     $total = 0.0;
     $productoBase = new Product();
     foreach ($carro as $key => $value) {
         $producto = $productoBase->getProductoById($key);
         $total = $total + $producto->getPrice() * $value;
         $this->_productos[] = array("_id" => $key, "name" => $producto->getName(), "description" => $producto->getDescription(), "price" => $producto->getPrice(), "quantity" => $value, "subTotal" => $producto->getPrice() * $value);
     }
     $this->_price = $total;
 }