Title placeholder

Hi

I would like to change the title placeholder for a specific custom post type. Looks like there is a filter available but i somehow cant get it to work.
https://wordpress.stackexchange.com/a/145331

function jam_title_placeholder( $title ){
    $screen = get_current_screen();

    // For CPT Lunch meny
    if  ( 'Lunch Meny' == $screen->post_type ) {
        $title = 'Veckonummer';
	}

    return $title;
}

add_filter( 'enter_title_here', 'jam_title_placeholder' );