modifyCopies newCopies = 
        return $ \oldCard -> 

    modifyCopies newCopies =
        return $ \oldCard ->

            in Just $ oldCard {quantity = newQuantity}

             in Just $ oldCard {quantity = newQuantity}

    modifyCategory categoryF = 
        return $ \oldCard -> 

    modifyCategory categoryF =
        return $ \oldCard ->

            in Just $ oldCard {Deck.category = newCategory}

             in Just $ oldCard {Deck.category = newCategory}

                (False, False) -> go (chunk (name x) [modifyCopies (const $ quantity y), modifyCategory (const . category $ y)] : acc) xs ys

                (False, False) ->
                    go
                        ( chunk
                            (name x)
                            [modifyCopies (const $ quantity y), modifyCategory (const . category $ y)]
                            : acc
                        )
                        xs
                        ys