docs: @Override
      public <G> Choice6<A, B, C, D, E, G> flatMap(
              Function<? super F, ? extends Monad<G, Choice6<A, B, C, D, E, ?>>> fn) {
          return match(Choice6::a, Choice6::b, Choice6::c, Choice6::d, Choice6::e, f -> fn.apply(f).coerce());
      }