Update Invoice API unable to add new line item

[temi]

Hello,

I have been working with the WHMCS api and am having an issue updating an invoice via the api. The goal is to add a new line item to a specific invoice, but even though the api returns a successful response, the new line item has not been added.

I am coding in python, and have formatted the request like this:

data = {
  "identifier": self.identifier,
  "secret": self.secret,
  "action": "UpdateInvoice",
  "invoiceid": invoiceid,
  "newitemdescription": ["Test Item"],
  "newitemamount": [10.00],
  "newitemtaxed": [False],
  "responsetype": "json"
}

r = requests.post(url, data, verify=False)

I've tried doing a dictionary like {"0": "Test Item"} a list of dictionaries [{"0": "Test Item"}] and using the next available invoice item id, but nothing has worked so far. Any suggestions to where I may be going wrong?

 

Thanks in advance

Edited April 7 by temi
formatting