public static function get_instance()
 {
     if (null == self::$instance) {
         self::$instance = new PageTemplater();
     }
     return self::$instance;
 }
 /**
  * Returns an instance of this class. 
  */
 public static function get_instance($templatePath, $templateName)
 {
     if (null == self::$instance) {
         self::$instance = new PageTemplater($templatePath, $templateName);
     }
     return self::$instance;
 }