@Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    Tuple2<?, ?> tuple2 = (Tuple2<?, ?>) o;
    return Objects.equals(f0, tuple2.f0) && Objects.equals(f1, tuple2.f1);
  }
@Test
  public void testEquals() {
    assertEquals(Tuple2.of(1, "a"), Tuple2.of(1, "a"));
    assertEquals(Tuple2.of(1, "a").hashCode(), Tuple2.of(1, "a").hashCode());
  }