API returning Request body is not a valid json object.

Hey guys, how are you doing today?

I'm using this library in a work project, but when I make the request, I'm getting as response: `{"status":"FAIL","code":"400008","errorMessage":"Request body is not a valid json object."}` I'm following your documentation, and this is the code I'm using to make the request:

```python3
parameters = {
"env": {
"terminalType": terminal_type,
},
"merchantTradeNo": order_id,
"orderAmount": order_amount,
"currency": currency,
"goods": items_list,
"buyer": {
"buyerName": {"firstName": first_name, "lastName": last_name},
"buyerEmail": email,
},
# "webhookUrl": settings.BINANCE_PAY_WEBHOOK_URL,
}
if client_ip is not None:
parameters["env"]["orderClientIp"] = client_ip
if middle_name is not None:
parameters["buyer"]["buyerName"]["middleName"] = middle_name
print("Parameters: {}".format(parameters))
return client.new_order(parameters)
```

I looked at your source code and the request body seems to be correctly formatted as json, so what is happening? Can someone help me with this?