public static function get_all_filters() {
        $filters = \core_component::get_component_classes_in_namespace('tool_usertours', 'local\filter');
        $filters = array_keys($filters);

        $filters = array_filter($filters, function($filterclass) {
            $rc = new \ReflectionClass($filterclass);
            return $rc->isInstantiable();
        });

        return $filters;
    }