/**
* Map the 6th element in a tuple to a different value
*
* @param fn Mapper function
* @return new Tuple8
*/
default <T> PTuple8<T1, T2, T3, T4, T5, T, T7, T8> map6(Function<T6, T> fn) {
if (arity() != 8) return (PTuple8) PTuple7.super.map6(fn);
return of(v1(), v2(), v3(), v4(), v5(), fn.apply(v6()), v7(), v8());
}
