protected function clearTransients()
    {
        // https://coderwall.com/p/yrqrkw/delete-all-existing-wordpress-transients-in-mysql-database
        // DELETE FROM `wp_options` WHERE `option_name` LIKE ('_transient_%');
        // DELETE FROM `wp_options` WHERE `option_name` LIKE ('_site_transient_%');
        Option::where('option_name', 'like', '_transient_%')->delete();
        Option::where('option_name', 'like', '_site_transient_%')->delete();
        return Option::where('option_name', 'like', '%_transient_%')->count();
    }