code: def clean_str(string, TREC=False):
      """
      Tokenization/string cleaning for all datasets except for SST.
      Every dataset is lower cased except for TREC
      """
      string = re.sub(r"[^A-Za-z0-9(),!?\'\`]", " ", string)
      string = re.sub(r"\'s", " 's", string)
      string = re.sub(r"\'ve", " 've", string)
      string = re.sub(r"n\'t", " n't", string)
      string = re.sub(r"\'re", " 're", string)
      string = re.sub(r"\'d", " 'd", string)
      string = re.sub(r"\'ll", " 'll", string)
      string = re.sub(r",", " , ", string)
      string = re.sub(r"!", " ! ", string)
      string = re.sub(r"\(", " \( ", string)
      string = re.sub(r"\)", " \) ", string)
      string = re.sub(r"\?", " \? ", string)
      string = re.sub(r"\s{2,}", " ", string)
      return string.strip() if TREC else string.strip().lower()
  
imports: import gzip
  import os
  import sys
  import re
  import random
  import numpy
  import torch
label_desc: Use image node_id 1 for calling a global function with example usage: clean_str(string, TREC) and returns: unknown