    "A comparator for [[Entry]]s which compares their items
     according to the given [[comparing]] function.

         value sortedEntries = map.sort(byItem(byIncreasing(String.lowercased)));

     This function is intended for use with [[Iterable.sort]]
     and [[Iterable.max]]."
    see (`function byKey`)
    tagged("Comparisons")
    shared Comparison byItem<Item>(Comparison comparing(Item x, Item y))
                (Object->Item x, Object->Item y)
            given Item satisfies Object =>
                    comparing(x.item, y.item);