### Question:
Tuple4 extends Tuple3<T1, T2, T3> implements Tuple { @Override public int hashCode() { return Objects.hash(super.hashCode(), item4); } Tuple4(T1 a, T2 b, T3 c, T4 d); static Tuple4<T1, T2, T3, T4> of(T1 a, T2 b, T3 c, T4 d); T4 getItem4(); @Override Object nth(int index); @Override Tuple4<T, T2, T3, T4> mapItem1(Function<T1, T> mapper); @Override Tuple4<T1, T, T3, T4> mapItem2(Function<T2, T> mapper); @Override Tuple4<T1, T2, T, T4> mapItem3(Function<T3, T> mapper); Tuple4<T1, T2, T3, T> mapItem4(Function<T4, T> mapper); @Override List<Object> asList(); @Override int size(); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void testHashCode() { Tuple4<Integer, Integer, Integer, Integer> same = Tuple4.of(1, 2, 3, 4); Tuple4<Integer, Integer, Integer, Integer> different = Tuple4.of(1, 2, 1, 4); assertThat(someTuple.hashCode()) .isEqualTo(same.hashCode()) .isNotEqualTo(different.hashCode()); }