code: def set_pairs(aishell1_md_file, wham_md_file, n_src):
      """set pairs of sources to make the mixture"""
      # Initialize list for pairs sources
      utt_pairs = []
      noise_pairs = []
      # In train sets utterance are only used once
      if "train" in aishell1_md_file.iloc[0]["subset"]:
          utt_pairs = set_utt_pairs(aishell1_md_file, utt_pairs, n_src)
          noise_pairs = set_noise_pairs(
              utt_pairs, noise_pairs, aishell1_md_file, wham_md_file
          )
      # Otherwise for dev we want 5000 mixtures
      elif "dev" in aishell1_md_file.iloc[0]["subset"]:
          utt_pairs = set_utt_pairs(aishell1_md_file, utt_pairs, n_src)[
              :5000
          ]
          noise_pairs = set_noise_pairs(
              utt_pairs, noise_pairs, aishell1_md_file, wham_md_file
          )
      # Otherwise for test we want 3000 mixtures
      else:
          utt_pairs = set_utt_pairs(aishell1_md_file, utt_pairs, n_src)[
              :3000
          ]
          noise_pairs = set_noise_pairs(
              utt_pairs, noise_pairs, aishell1_md_file, wham_md_file
          )
  
      return utt_pairs, noise_pairs
  
imports: import argparse
  import os
  import random
  import warnings
  import numpy
  import pandas
  import pyloudnorm
  import soundfile
  from tqdm import tqdm
label_desc: Use image node_id 5 for calling a global function with example usage: set_pairs(aishell1_md_file, wham_md_file, n_src) and returns: utt_pairs,  noise_pairs