static <A> S safeMapToLines(Iterable<A> l, IF1<A, S> f) {
  ret mapToLines(f, l);
}

static <A> S safeMapToLines(IF1<A, S> f, Iterable<A> l) {
  ret mapToLines(f, l);
}

static <A, B> S safeMapToLines(Map<A, B> map, IF2<A, B, S> f) {
  ret mapToLines(map, f);
}