woocommerce通过编程添加多个产品

hello I want to know how to add multiple products in a order using coding. I'm currently using this code

 $address = array(
        'first_name' => 'random',
        'last_name'  => 'random',
        'company'    => '',
        'email'      => 'random@random.com',
        'phone'      => '987987987987',
        'address_1'  => 'hawa hawa havai',
        'address_2'  => '', 
        'city'       => 'Delhi',
        'state'      => 'New Delhi',
        'postcode'   => '11447788',
        'country'    => 'IN'
    );

    $order = wc_create_order();
    $order->add_product( wc_get_product('819'), 2 ); //(get_product with id and next is for quantity)
    $order->set_address( $address, 'billing' );
    $order->set_address( $address, 'shipping' );
    $order->calculate_totals();

I'm successfully able to add one product but how to add multiple products at same time. I tried this code but doesn't helped.

UPDATE 1

this code works

$order = wc_create_order();
$order->add_product( wc_get_product('819'), 2 ); // 819, 815... etc are product id.
$order->add_product( wc_get_product('815'), 1 ); // 2, 1, 3 are quantity of products.
$order->add_product( wc_get_product('835'), 3 ); 
$order->set_address( $address, 'billing' );
$order->set_address( $address, 'shipping' );
$order->calculate_totals();