anchor.diff:      }
     }
   
  -  public final void delink()
  +  private void delink()
     {
       checkValidity();
       _delinking = true;
  
positive.code:     return _created;
    }
  
    public final boolean isValid()
    {
      return null != _repository;
  
negative.code:     }
    }
  
    @Override
    public final void link()
    {
      checkValidity();
  