change external product url in woocommerce

gistfile1.txt

function override_external_product_url( $url, $product )
{
    if ( 'external' === $product->get_type() ) 
    {
        $url = 'https://biawp.ir';
    }
    return $url;
}
add_filter( 'woocommerce_product_add_to_cart_url', 'override_external_product_url', 10, 2 );