code: public static <T, V extends Comparable<? super V>, L extends List<T>> L sortThisBy(L list, Function<? super T, ? extends V> function)
      {
          return Iterate.sortThis(list, Comparators.byFunction(function));
      }
docs: Sort the list by comparing an attribute defined by the function.
  SortThisBy is a mutating method.  The List passed in is also returned.