docs: def generate_captcha(self):
          """Generated a fresh captcha
  
          This method randomly generates a simple captcha question. It then
          generates a timestamp for the current time, and signs the answer
          cryptographically to protect against tampering and replay attacks.
          """
          # Generate a fresh question
          self._question, answer = self._generate_question()
  
          # Get the current time, then sign the answer cryptographically
          timestamp = time.time()
          hashed = self.hash_answer(answer, timestamp)
  
          # Now stash all our values
          self._values = ['', timestamp, hashed]