It is just for approximations. For instance, you can see in approx. "ı" => "ı". When I want to "hafıza" => "hafıza" in spec test, it looks "hafÄ±za" that is not Turkish. The reason is value  = object[1].unpack("C*") in this line. I thought that if I use "U" pack, I can get Turkish approximations clearly.