code: def normalize(string):
      """
      This function normalizes a given string according to
      the normalization rule
      The normalization rule removes "/" indicating filler words,
      removes "+" indicating repeated words,
      removes all punctuation marks,
      removes non-speech symbols,
      and extracts orthographic transcriptions.
  
      Arguments
      ---------
      string : str
          The string to be normalized
  
      Returns
      -------
      str
          The string normalized according to the rules
  
      """
      # extracts orthographic transcription
      string = re.sub(r"\(([^)]*)\)\/\(([^)]*)\)", r"\1", string)
      # removes non-speech symbols
      string = re.sub(r"n/|b/|o/|l/|u/", "", string)
      # removes punctuation marks
      string = re.sub(r"[+*/.?!,]", "", string)
      # removes extra spaces
      string = re.sub(r"\s+", " ", string)
      string = string.strip()
  
      return string
  
file_path: speechbrain/recipes/KsponSpeech/ksponspeech_prepare.py
imports: import csv
  import logging
  import os
  import re
  import torchaudio
  from speechbrain.dataio.dataio import load_pkl, merge_csvs, save_pkl
  from speechbrain.utils.data_utils import get_all_files
label_desc: Use image node_id 5 for calling a global function with example usage: normalize(string) and returns: string