code: def obfuscate_class(tokens, index, replace, replacement, *args):
      
      def return_replacement(replacement):
          CLASS_REPLACEMENTS[replacement] = replace
          return replacement
      tok = tokens[index]
      token_type = tok[0]
      token_string = tok[1]
      prev_tok = tokens[index-1]
      prev_tok_string = prev_tok[1]
      if token_type != tokenize.NAME:
          return None # Skip this token
      if token_string.startswith('__'):
          return None
      if prev_tok_string != '.':
          if token_string == replace:
              return return_replacement(replacement)
docs: If the token string (a class) inside *tokens[index]* matches *replace*,
      return *replacement*.