code: public static function GetAuthClass () {
  		if (self::$authClass === NULL) {
  			if (class_exists(self::AUTH_CLASS_FULL)) {
  				self::$authClass = self::AUTH_CLASS_FULL;
  			} else {
  				self::$authClass = self::AUTH_CLASS_BASIC;
  			}
  		}
  		return self::$authClass;
  	}
docs: Return authentication module full class name.
  @return string|NULL