Jetpack Infinite Scroll – changing number of posts

Found the code that works here:

https://themeshaper.com/2013/10/08/how-to-override-jetpack-infinite-scroll-settings-in-a-child-theme/

 /*
 * Change the posts_per_page Infinite Scroll setting from 10 to 20
 */
function my_theme_infinite_scroll_settings( $args ) {
    if ( is_array( $args ) )
        $args['posts_per_page'] = 20;
    return $args;
}
add_filter( 'infinite_scroll_settings', 'my_theme_infinite_scroll_settings' );