code: public static <R, S> Tuple2<R, S> create(R r, S s) {
          return new Tuple2<R, S>(r, s);
      }
docs: Returns a new instance.
  
  @param r
  first element
  @param s
  second element
  @param <R> type of first element
  @param <S>
  type of second element
  
  @return tuple