code: def optimize_fn(item):
      return torch.arange(item[0], item[0] + 20).to(torch.int)
  
imports: import os
  import sys
  from time import sleep
  from unittest import mock
  import numpy
  import pytest
  import torch
  from lightning import seed_everything
  from lightning.data.streaming import Cache, functions
  from lightning.data.streaming.dataloader import StreamingDataLoader
  from lightning.data.streaming.dataset import _INDEX_FILENAME, Dir, RemoteDir, StreamingDataset, _associate_chunks_to_workers, _replay_chunks_sampling, _replay_sampling, _should_replace_path, _try_create_cache_dir
  from lightning.data.streaming.item_loader import TokensLoader
  from lightning.data.streaming.shuffle import FullShuffle, NoShuffle
  from lightning.data.utilities.env import Environment, _DistributedEnv, _WorkerEnv
  from torch.utils.data import DataLoader
label_desc: Use image node_id 12 for calling a global function with example usage: optimize_fn(item) and returns: torch