Annoying message won’t go away

I am getting an annoying message that won’t go away: “Did you know Autoptimize includes on-the-fly image optimization (with support for WebP) and CDN via ShortPixel? Check out the Autoptimize Image settings to activate this option.”

You mention in the forums that we should add the code snippet below to make it go away. Where do we need to add that code snipped. In header.php? Somewhere else.

Thanks,
Marko

add_filter(‘autoptimize_filter_main_imgopt_plug_notice’,’no_aosp_notice’);
function no_aosp_notice() {
return ”;
}