code: def merge_datasets(idir):
      sys.argv = [
          sys.argv[0],
          "--input",
          idir,
          "--output-prefix",
          os.path.join(idir, "merge"),
          "--multimodal",
      ]
      merge_main()
  
file_path: megatron-lm/tests/unit_tests/data/test_preprocess_mmdata.py
imports: import os
  import random
  import sys
  import tempfile
  import nltk
  import numpy
  from megatron.core.datasets.indexed_dataset import MMapIndexedDataset
  from tests.unit_tests.data.test_preprocess_data import dummy_jsonl, gpt2_vocab, gpt2_merge
  from tools.merge_datasets import main
  from tools.preprocess_mmdata import Encoder
  from tools.preprocess_mmdata import get_args
  from tools.preprocess_mmdata import main
label_desc: Use image node_id 3 for calling a global function with example usage: merge_datasets(idir) without return types