display navigation, custom code is not working

Hi there,
I need to hide the Navigation post for specific category, post or page and I have found this function in Customizr website, but it doesn’t work.

add_action ( 'wp_head', 'remove_single_post_nav_links');
function remove_single_post_nav_links() {
    //we only want to remove those nav links for a single post and not for the list of posts
    if ( !is_single() )
        return;
        remove_action  ( '__after_loop' , array( CZR_post_navigation::$instance , 'tc_post_nav' ), 20 );
}

Have you an updated code please?