code: def clean_dataframe(df):
      # Drop unecessary columns
      df.drop(
          [
              "utt_id",
              "file",
              "lvl",
              "channel",
              "rir_channel",
              "words",
              "file",
              "rir",
          ],
          axis=1,
          inplace=True,
      )
  
      # Sort by start/stop
      df = df.groupby("session_id").apply(
          lambda x: x.sort_values("start")
      )
      df = pd.melt(df, id_vars=["session_id", "start"])
      df.drop(["variable"], axis=1, inplace=True)
      df.rename({"value": "stop"}, axis=1, inplace=True)
      return df
  
file_path: speechbrain/recipes/LibriParty/VAD/libriparty_prepare.py
imports: import numpy
  import pandas
  import json
  import logging
  from collections import OrderedDict
label_desc: Use image node_id 2 for calling a global function with example usage: clean_dataframe(df) and returns: df