Не приходит json ответ от api WayForPay

@bot.message_handler(commands=['buy'])
def create_invoice(self, data, return_url=""):
    def __init__(self, merchant_account, merchant_key, merchant_domain):
        self.merchant_account = "****"
        self.merchant_key = "****"
        self.merchant_domain = "***"

    signature_data = f"{self.merchant_account};{self.merchant_domain};1;0;UAH"
    params = {
        "transactionType":"CREATE_INVOICE",
        "merchantAccount":"test_merch_n1",
        "merchantAuthType":"SimpleSignature",
        "merchantDomainName":"https://t.me/account_shop_FB_BOT",
        "merchantSignature":generate_signature(self.merchant_key, signature_data),
        "apiVersion":1,
        "language":"ru",
        "serviceUrl":"http://serviceurl.com",
        "orderReference":"myOrder1",
        "orderDate":1421412898,
        "amount":1547.36,
        "currency":"UAH",
        "orderTimeout": 86400,
        "productName":["Samsung WB1100F","Samsung Galaxy Tab 4 7.0 8GB 3G Black"],
        "productPrice":[21.1,30.99],
        "productCount":[1,2],
        "paymentSystems": "card;privat24",
        "clientFirstName":"Bulba",
        "clientLastName":"Taras",
        "clientPhone":"380556667788"
    }
    def _query(self, params, url=API_URL):
        response = requests.post(url, json=params)
        return response.json()

На выводе ничего нету