/** * Lazily Map 4th element and memoise the result * * @param fn Map function * @return */ default <T> PTuple8<T1, T2, T3, T, T5, T6, T7, T8> lazyMap4(Function<T4, T> fn) { if (arity() != 8) return (PTuple8) PTuple7.super.lazyMap4(fn); return new LazyMap4PTuple8(fn, (PTuple8) this); }