curl --request POST \
  --url https://api.example.com/fill \
  --header 'Content-Type: application/x-www-form-urlencoded' \
  --data 'file_id=<string>' \
  --data 'prompt=<string>'

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>"
    }
  ]
}