code: def create_empty_mixture_md(n_src, subdir):
      """Create the mixture dataframe"""
      mixture_dataframe = pd.DataFrame()
      mixture_dataframe["mixture_ID"] = {}
      mixture_dataframe["mixture_path"] = {}
      if subdir == "mix_clean":
          for i in range(n_src):
              mixture_dataframe[f"source_{i + 1}_path"] = {}
      elif subdir == "mix_both":
          for i in range(n_src):
              mixture_dataframe[f"source_{i + 1}_path"] = {}
          mixture_dataframe[f"noise_path"] = {}
      elif subdir == "mix_single":
          mixture_dataframe["source_1_path"] = {}
          mixture_dataframe[f"noise_path"] = {}
      mixture_dataframe["length"] = {}
      return mixture_dataframe
  
imports: import os
  import argparse
  import soundfile
  import pandas
  import numpy
  import functools
  from scipy.signal import resample_poly
  import tqdm.contrib.concurrent
  import glob
  import shutil
label_desc: Use image node_id 7 for calling a global function with example usage: create_empty_mixture_md(n_src, subdir) and returns: mixture_dataframe