code: def unpack_dataset(folder, threads=8):
      case_identifiers = get_case_identifiers(folder)
      p = Pool(threads)
      npz_files = [
          os.path.join(folder, i + ".npz") for i in case_identifiers
      ]
      p.map(convert_to_npy, npz_files)
      p.close()
      p.join()
  
file_path: medicaldetectiontoolkit/experiments/lidc_exp/pack_dataset.py
imports: import numpy
  from multiprocessing import Pool
  import os
  import subprocess
label_desc: Use image node_id 3 for calling a global function with example usage: unpack_dataset(folder, threads) without return types