WC_Admin_Settings::add_message PHP Method

        public static function add_message($text)
        {
            self::$messages[] = $text;
        }

 public function save_settings()
 {
     WC_Admin_Settings::save_fields($this->settings);
     $is_api_working = $this->check_api() ? 1 : 0;
     update_option(WC_SiftScience_Options::$is_api_setup, $is_api_working);
     if ($is_api_working === 1) {
         WC_Admin_Settings::add_message('API is correctly configured');
     } else {
         WC_Admin_Settings::add_error('API settings are broken');
     }
 }