code: def add_noise(infile, snrs, noise_manifest, out_dir, num_workers=1):
      allrows = []
  
      with open(infile, "r") as inf:
          for line in inf:
              row = json.loads(line.strip())
              row["snrs"] = snrs
              row["out_dir"] = out_dir
              row["noise_manifest"] = noise_manifest
              row["input_manifest"] = infile
              allrows.append(row)
      pool = multiprocessing.Pool(num_workers)
      pool.map(process_row, allrows)
      pool.close()
      print("Done!")
  
file_path: NeMo/scripts/dataset_processing/add_noise.py
imports: import argparse
  import copy
  import json
  import multiprocessing
  import os
  import random
  import numpy
  import soundfile
  from nemo.collections.asr.parts.preprocessing.perturb import NoisePerturbation
  from nemo.collections.asr.parts.preprocessing.segment import AudioSegment
label_desc: Use image node_id 4 for calling a global function with example usage: add_noise(infile, snrs, noise_manifest, out_dir, num_workers) without return types