static <A> L<A> mostPopularEntriesFromMultiMap(MultiSet<A> ms) {
  ret mostPopularEntriesFromMultiMap(10, ms);
}

static <A> L<A> mostPopularEntriesFromMultiMap(int n, MultiSet<A> ms) {
  ret ms == null ? emptyList() : ms.getTopTen(n);
}