code: def test_duplicate(ray_start_regular_shared):
      it = from_range(5, num_shards=1)
  
      it1, it2 = it.gather_sync().duplicate(2)
      it1 = it1.batch(2)
  
      it3 = it1.union(it2, deterministic=False)
      results = it3.take(20)
      assert results == [0, [0, 1], 1, 2, [2, 3], 3, 4, [4]]
  
imports: import sys
  import time
  import collections
  from collections import Counter
  import pytest
  import ray
  from ray.util.iter import from_items, from_iterators, from_range, from_actors, ParallelIteratorWorker, LocalIterator
  from ray._private.test_utils import Semaphore
label_desc: Use image node_id 16 for calling a global function with example usage: test_duplicate(ray_start_regular_shared) without return types