public <V> UnifiedSetMultimap<V, T> groupByEach(
     Function<? super T, ? extends Iterable<V>> function) {
   return this.groupByEach(function, UnifiedSetMultimap.<V, T>newMultimap());
 }
 public <V> UnifiedSetMultimap<V, T> groupBy(Function<? super T, ? extends V> function) {
   return this.groupBy(function, UnifiedSetMultimap.<V, T>newMultimap());
 }