public static <T> Partition<T> of(
      int numPartitions,
      PartitionWithSideInputsFn<? super T> partitionFn,
      Requirements requirements) {
    Contextful ctfFn =
        Contextful.fn(
            (T element, Contextful.Fn.Context c) ->
                partitionFn.partitionFor(element, numPartitions, c),
            requirements);
    return new Partition<>(new PartitionDoFn<T>(numPartitions, ctfFn, partitionFn));
  }
@Test
  public void testPartitionGetName() {
    assertEquals("Partition", Partition.of(3, new ModFn()).getName());
  }