void () { update(x -> x.flatMap(y -> Optional.empty())); update(x -> x.flatMap(y -> x.flatMap(z -> Optional.empty()))); update(x -> x.flatMap(y -> x.flatMap(z -> x.flatMap(w -> Optional.empty())))); update(x -> { return x.flatMap(y -> { return x.flatMap(z -> { return x.flatMap(w -> { return Optional.empty(); }); }); }); }); }