Create Custom Product Type extend WC_Booking

Im trying to make a new Custom Product Type, but I want it to have the same base functionalities as a Bookable Product from the WC Bookings plugin. I know I can create a new product type with following code:

function wp2_register_group_activity_product_type () {

    class WC_Group_Activity extends WC_Product {

        public function __construct( $product ) {
            $this->product_type = 'group_activity'; // name of your custom product type
            parent::__construct( $product );
            // add additional functions here
        }
    }
}

But following code does not seem to work:

class WC_Group_Activity extends WC_Product_Booking {

Any help or direction is appreciated!