Gotta be a better way to get an array of Child Page IDs than this. WordPress

wordpress-get-child-page-ids.php

<?php
// basic idea here is a common function to pass a parent page ID
// and get back an array of it and its child page IDs only
function getChildPageIDs( $id ) {

	$child_pages   = get_pages('child_of='.$id);
	$ids_to_remove = array($id); // we want to remove parent id too
	foreach($child_pages as $child) {
		array_push($ids_to_remove,$child->ID); // for every child add the id into array
	}
	return $ids_to_remove; // send it all back

}

return getChildPageIDs( '123' );

// there's gotta be a better way to do this no?