/**
  * Comparator factory instance
  * 
  * @return \SebastianBergmann\Comparator\Factory
  */
 public static function getComparatorFactory()
 {
     if (self::$_comparatorFactory === null) {
         self::$_comparatorFactory = new \SebastianBergmann\Comparator\Factory();
     }
     return self::$_comparatorFactory;
 }