docs: static <T> Iterable<T> annotateEmptyStrings(Iterable<T> items) {
      if (Iterables.contains(items, "")) {
        List<T> annotatedItems = Lists.newArrayList();
        for (T item : items) {
          if (Objects.equal(item, "")) {
            // This is a safe cast because know that at least one instance of T (this item) is a
            // String.
            @SuppressWarnings("unchecked")
            T newItem = (T) HUMAN_UNDERSTANDABLE_EMPTY_STRING;
            annotatedItems.add(newItem);
          } else {
            annotatedItems.add(item);
          }
        }
        return annotatedItems;
      } else {
        return items;
      }
    }