code: def check_already_generated(md_dir):
      """Check if files have already been generated"""
      # Get the already generated files
      already_generated_csv = os.listdir(md_dir)
      # Data directories in wham_noise
      wham_noise_dirs = ["cv", "tr", "tt"]
      # Save the already data directories names
      already_processed_dir = [
          f.replace("test", "tt")
          .replace("train", "tr")
          .replace("dev", "cv")
          .replace(".csv", "")
          for f in already_generated_csv
      ]
      # Actual directories that haven't already been processed
      not_already_processed_dir = list(
          set(wham_noise_dirs) - set(already_processed_dir)
      )
      return not_already_processed_dir
  
file_path: speechbrain/recipes/Aishell1Mix/separation/scripts/create_wham_metadata.py
imports: import os
  import argparse
  import soundfile
  import pandas
  import glob
  from tqdm import tqdm
label_desc: Use image node_id 3 for calling a global function with example usage: check_already_generated(md_dir) and returns: not_already_processed_dir