public function __construct($app = null)
{
if (is_object($app)) {
$this->app = $app;
} else {
$this->app = mw();
}
$tables['cart'] = 'cart';
$tables['cart_orders'] = 'cart_orders';
$tables['cart_shipping'] = 'cart_shipping';
$tables['cart_taxes'] = 'cart_taxes';
$this->tables = $tables;
}