Cacher is the code snippet organizer for pro developers

function add_custom_body_class( $classes ) {
    global $post;

    $parent = array_reverse(get_post_ancestors($post->ID));
    $page_parent = get_page($parent[0]);

    if ($page_parent->post_name === 'shingaku') {
        $classes[] = 'parent-page-shingaku';
    }

    return $classes;


}