Plugin throws error

Hi Richard

We are using this snippet to get sub page by slug something like wp-json/wp/v2/pages?path=/parent-slug/child-slug

add_filter('rest_page_query', function ($args, $request){
$path = $request->get_param('path');
if (!empty($path)) {
$pageByPath = get_page_by_path($path, OBJECT, 'page');
// overwrite the page id with the page id by path
$args['p'] = $pageByPath->ID;
}
return $args;
}, 10, 2);

When we install your plugin it throws error.