static <A extends Iterable> A pnl(S prefix default "", A l) {
  printNumberedLines(prefix, l);
  ret l;
}

static <A> A[] pnl(S prefix default "", A[] l) {
  printNumberedLines(prefix, l);
  ret l;
}

static <A extends Map> A pnl(A map) {
  printNumberedLines(map);
  ret map;
}

static <A extends Map> A pnl(S prefix, A map) {
  printNumberedLines(prefix, map);
  ret map;
}

sS pnl(S s) {
  printNumberedLines(lines(s));
  ret s;
}

ifclass MultiSet
static <A> MultiSet<A> pnl(MultiSet<A> ms) {
  pnl(ms == null ? null : ms.asMap());
  ret ms;
}
endif

ifclass MultiMap
static <A, B> MultiMap<A, B> pnl(MultiMap<A, B> mm) {
  pnl(mm == null ? null : mm.asMap());
  ret mm;
}
endif

Began life as a copy of #1006335