static Map mapNonNullsToValue(Iterable l, O f) {
  ret mapNonNullsToValue(f, l);
}

static Map mapLike mapNonNullsToValue(O f, Iterable l) {
  new HashMap map;
  if (l != null) for (O o : l) {
    O val = callF(f, o);
    if (val != null)
      map.put(o, val);
  }
  ret map;
}

static <A, B, C> Map<A, C> mapNonNullsToValue(Map<A, B> map, IF2<A, B, C> f) {
  new HashMap map2;
  if (map != null) for (O key, value : map) {
    O val = callF(f, key, value);
    if (val != null)
      map2.put(key, val);
  }
  ret map2;
}


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

static <A, B> Map<A, B> mapNonNullsToValue(IF1<A, B> f, Iterable<A> l) {
  ret mapNonNullsToValue((O) f, l);
}

Began life as a copy of #1021879