code: def get_index_dir():
      """Create sub-directory for this index."""
  
      args = get_retro_args()
  
      # Directory path.
      index_dir_path = os.path.join(
          args.retro_workdir,
          "index",
          args.retro_index_type,
          args.retro_index_str,
      )
  
      # Make directory.
      os.makedirs(index_dir_path, exist_ok=True)
  
      return index_dir_path
  
file_path: megatron-lm/tools/retro/index/utils.py
imports: import concurrent
  import gc
  import glob
  import numpy
  import os
  import psutil
  import time
  import torch
  from tqdm import tqdm
  from megatron import get_retro_args, print_rank_0
  from tools.retro.db.utils import get_indexed_dataset_infos
  from tools.retro.external_libs import h5py
label_desc: Use image node_id 1 for calling a global function with example usage: get_index_dir() and returns: index_dir_path