code: def normalize_answer(s):
      """Lower text and remove punctuation, articles and extra whitespace.
      From official ReCoRD eval script
      """
  
      def remove_articles(text):
          return re.sub(r"\b(a|an|the)\b", " ", text)
  
      def white_space_fix(text):
          return " ".join(text.split())
  
      def remove_punc(text):
          exclude = set(string.punctuation)
          return "".join(ch for ch in text if ch not in exclude)
  
      def lower(text):
          return text.lower()
  
      return white_space_fix(remove_articles(remove_punc(lower(s))))
  
imports: import re
  import string
  import collections
label_desc: Use image node_id 1 for calling a global function with example usage: normalize_answer(s) and returns: white_space_fix, re, str, str, text