code: static <K, V> ImmutableListMultimap<K, V> fromMapEntries(
        Collection<? extends Map.Entry<? extends K, ? extends Collection<? extends V>>> mapEntries,
        @NullableDecl Comparator<? super V> valueComparator) {
      if (mapEntries.isEmpty()) {
        return of();
      }
      ImmutableMap.Builder<K, ImmutableList<V>> builder =
          new ImmutableMap.Builder<>(mapEntries.size());
      int size = 0;
  
      for (Entry<? extends K, ? extends Collection<? extends V>> entry : mapEntries) {
        K key = entry.getKey();
        Collection<? extends V> values = entry.getValue();
        ImmutableList<V> list =
            (valueComparator == null)
                ? ImmutableList.copyOf(values)
                : ImmutableList.sortedCopyOf(valueComparator, values);
        if (!list.isEmpty()) {
          builder.put(key, list);
          size += list.size();
        }
      }
  
      return new ImmutableListMultimap<>(builder.build(), size);
    }
docs: Creates an ImmutableListMultimap from an asMap.entrySet.