parent_dropdown( int $default_page = 0, int $parent_page = 0, int $level = 0, int|WP_Post $post = null ): void|false

937function parent_dropdown( $default_page = 0, $parent_page = 0, $level = 0, $post = null ) {938	global $wpdb;939 940	$post  = get_post( $post );941	$items = $wpdb->get_results(942		$wpdb->prepare(943			"SELECT ID, post_parent, post_title944			FROM $wpdb->posts945			WHERE post_parent = %d AND post_type = 'page'946			ORDER BY menu_order",947			$parent_page948		)949	);950 951	if ( $items ) {952		foreach ( $items as $item ) {953			// A page cannot be its own parent.954			if ( $post && $post->ID && (int) $item->ID === $post->ID ) {955				continue;956			}957 958			$pad      = str_repeat( '&nbsp;', $level * 3 );959			$selected = selected( $default_page, $item->ID, false );960 961			echo "\n\t<option class='level-$level' value='$item->ID' $selected>$pad " . esc_html( $item->post_title ) . '</option>';962			parent_dropdown( $default_page, $item->ID, $level + 1 );963		}964	} else {965		return false;966	}967}