Programmatically clearing cache not working

Hi, following this support reply I’ve added this code to functions.php:

add_action( 'save_post', 'wd_docket_cache_flush', 10, 3 );

function wd_docket_cache_flush( $post_id, $post, $update ) {
wp_cache_flush();
}

But when I create and save a new page and then check the Docket Cache config page, the caches aren’t being cleared. Am I missing something?

Thanks.