code: public static <S, T> Function<Pair<S, T>, Pair<T, S>> swappedPair()
      {
          return (Function<Pair<S, T>, Pair<T, S>>) (Function<?, ?>) SWAPPED_PAIR_FUNCTION;
      }
docs: Swap the input pair and return the swapped pair.
  
  @return A function that gets the swapped pair {@code Iterable}