How to use interface diff?

I would like to compare the subtle difference between annotations. However, I'm receiving the following error by trying to use interface diff. Is there more detailed documentation on how to use diff? Thanks.

image

Hi! If you haven't seen it yet, the expected JSON format is documented here: https://prodi.gy/docs/api-interfaces#diff

For example, your JSON format could look like this:

{
  "accept": {
      "text": "Cyber researchers have linked the vulnerability exploited by the latest ransomware to “WannaCry”. Both versions of malicious software rely on weaknesses discovered by the National Security Agency years ago, Kaspersky said."
  },
  "reject": {
      "text": "Cyber researchers linked the vulnerability exploited by the latest ransomware to 'Wanna Cry'. Both versions of malicious software rely on weaknessses, discovered by the National Security Agency years ago, Kaspersky said"
  }
}

(If you're on Prodigy v1.10, you can also provide the two texts to diff via the keys "added" and "removed".)