How to use the werobot.utils.get_signature function in WeRoBot

def tester(app, token, endpoint):
        test_app = webtest.TestApp(app)

        response = test_app.get(endpoint, expect_errors=True)
        assert response.status_code == 403

        timestamp = str(time.time())
        nonce = str(random.randint(0, 10000))
        signature = get_signature(token, timestamp, nonce)
        echostr = generate_token()

        params = "?timestamp=%s&nonce=%s&signature=%s&echostr=%s" % (
            timestamp, nonce, signature, echostr
        )
        response = test_app.get(endpoint + params)

        assert response.status_code == 200
        assert response.body.decode('utf-8') == echostr

        response = test_app.get(endpoint, expect_errors=True)

        assert response.status_code == 403
        assert response.body.decode('utf-8') == u'喵'

        xml = """

def test_tornado(self):
            token = self.token
            timestamp = str(time.time())
            nonce = str(random.randint(0, 10000))
            signature = get_signature(token, timestamp, nonce)
            echostr = generate_token()

            params = "?timestamp=%s&nonce=%s&signature=%s&echostr=%s" % (
                timestamp, nonce, signature, echostr
            )

            response = self.fetch(path=self.endpoint + params)
            assert response.code == 200
            assert response.body.decode('utf-8') == echostr

            response = self.fetch(path=self.endpoint, )
            assert response.code == 403
            assert response.body.decode('utf-8') == u'喵'

            xml = """

)
    )

    from django.test.utils import setup_test_environment
    setup_test_environment()
    from django.test.client import Client
    from werobot.parser import parse_xml, process_message
    import django

    django.setup()
    client = Client()

    token = 'TestDjango'
    timestamp = str(time.time())
    nonce = str(random.randint(0, 10000))
    signature = get_signature(token, timestamp, nonce)
    echostr = generate_token()

    response = client.get(
        '/robot/', {
            'signature': signature,
            'timestamp': timestamp,
            'nonce': nonce,
            'echostr': echostr
        }
    )
    assert response.status_code == 200
    assert response.content.decode('utf-8') == echostr

    xml = """
    

def encrypt_message(self, reply, timestamp=None, nonce=None):
        """
        加密微信回复
        :param reply: 加密前的回复
        :type reply: WeChatReply 或 XML 文本
        :return: 加密后的回复文本
        """
        if hasattr(reply, "render"):
            reply = reply.render()

        timestamp = timestamp or to_text(int(time.time()))
        nonce = nonce or generate_token(5)
        encrypt = to_text(self.prp_crypto.encrypt(reply, self.app_id))
        signature = get_signature(self.token, timestamp, nonce, encrypt)
        return to_text(
            self.ENCRYPTED_MESSAGE_XML.format(
                encrypt=encrypt,
                signature=signature,
                timestamp=timestamp,
                nonce=nonce
            )

def decrypt_message(self, timestamp, nonce, msg_signature, encrypt_msg):
        """
        解密收到的微信消息
        :param timestamp: 请求 URL 中收到的 timestamp
        :param nonce: 请求 URL 中收到的 nonce
        :param msg_signature: 请求 URL 中收到的 msg_signature
        :param encrypt_msg: 收到的加密文本. ( XML 中的  部分 )
        :return: 解密后的 XML 文本
        """
        signature = get_signature(self.token, timestamp, nonce, encrypt_msg)
        if signature != msg_signature:
            raise InvalidSignature(msg_signature)
        return self.prp_crypto.decrypt(encrypt_msg, self.app_id)