static <A, B> MultiSet<B> lambdaMapLike mapToMultiSet(IF1<A, B> f, A[] l) {
  new MultiSet<B> ms;
  if (l != null) for ping (A o : l)
    ms.add(f.get(o));
  ret ms;
}

static <A, B> MultiSet<B> lambdaMapLike mapToMultiSet(IF1<A, B> f, Iterable<A> l) {
  new MultiSet<B> ms;
  if (l != null) for ping (A o : l)
    ms.add(f.get(o));
  ret ms;
}

static <A, B> MultiSet<B> mapToMultiSet(A[] l, IF1<A, B> f) {
  ret mapToMultiSet(f, l);
}

static <A, B> MultiSet<B> mapToMultiSet(Iterable<A> l, IF1<A, B> f) {
  ret mapToMultiSet(f, l);
}

Began life as a copy of #1003239