code: def _tokenize_sexpr(s):
      tokker = re.compile(r" +|[()]|[^ ()]+")
      toks = [
          t
          for t in [match.group(0) for match in tokker.finditer(s)]
          if t[0] != " "
      ]
      return toks
  
imports: import re
  import codecs
  import random
  from collections import Counter
label_desc: Use image node_id 3 for calling a global function with example usage: _tokenize_sexpr(s) and returns: toks