code: def cookie_encode(data, key, digestmod=None):
      
      depr(0, 13, "cookie_encode() will be removed soon.",
                  "Do not use this API directly.")
      digestmod = digestmod or hashlib.sha256
      msg = base64.b64encode(pickle.dumps(data, -1))
      sig = base64.b64encode(hmac.new(tob(key), msg, digestmod=digestmod).digest())
      return tob('!') + sig + tob('?') + msg
docs: Encode and sign a pickle-able object. Return a (byte) string