code: def normalize_whitespaces(sentence):
      return MULTI_WHITESPACES_REGEX.sub(" ", sentence).strip()
  
imports: import parlai.core.build_data
  import glob
  import gzip
  import multiprocessing
  import os
  import re
  import sys
  import time
  import tqdm
  import xml.etree.ElementTree
  from parlai.core.build_data import DownloadableFile
  from parlai.utils.io import PathManager
label_desc: Use image node_id 4 for calling a global function with example usage: normalize_whitespaces(sentence) and returns: MULTI_WHITESPACES_REGEX