public function save_changes($data) {
        $data = (array) $data;
        unset($data['filter']);
        unset($data['contextid']);
        foreach ($data as $name => $value) {
            if ($value !== '') {
                filter_set_local_config($this->filter, $this->context->id, $name, $value);
            } else {
                filter_unset_local_config($this->filter, $this->context->id, $name);
            }
        }
    }