anchor.diff:                               yield input [ 
                                       HTMLAttr.Type "text"
                                       Name "Link"
  +                                    Value (U2.Case1 model.NewBook.Link)
                                       ClassName "form-control"
                                       Placeholder "Please insert link"
                                       Required true
  
positive.code:                              yield input [
                                       HTMLAttr.Type "text"
                                       Name "Title"
                                       ClassName "form-control"
                                       Placeholder "Please insert book title"
                                       Required true
  
negative.code:     | AddBook ->
          if Validation.verifyBook model.NewBook then
              let wishList = { model.WishList with Books = (model.NewBook :: model.WishList.Books) |> List.sortBy (fun b -> b.Title) }
              { model with WishList = wishList; NewBook = Book.empty }, postWishListCmd(model.Token,wishList)
          else
              { model with 
                  TitleErrorText = Validation.verifyBookTitle model.NewBook.Title
  