code: def lexify(self, text='????', letters=string.ascii_letters):
          
          return _re_qm.sub(lambda x: self.random_element(letters), text)
docs: Replaces all question mark ('?') occurrences with a random letter.
  
          :param text: string to be parsed
          :param letters: a set of letters to choose from.
          :returns: string with all letter placeholders filled in