public static function get_instance($options_id = '')
{
if (self::$instance === null) {
if (empty($options_id)) {
throw new Exception('URE_Lib::get_inctance() - Error: plugin options ID string is required');
}
// new static() will work too
self::$instance = new URE_Lib($options_id);
}
return self::$instance;
}
