curl --request PUT \
  --url https://api.soundpiece.co/v1/create.new_instrumental \
  --header 'Content-Type: application/json' \
  --data '
{
  "idempotency_key": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "reference": {
    "url": "<string>"
  },
  "callback_url": "<string>"
}
'

{
  "instrumental": {
    "id": "<string>",
    "created_at": "2023-11-07T05:31:56Z",
    "idempotency_key": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "prompt": "<string>",
    "reference": {
      "url": "<string>"
    },
    "outputs": [
      {
        "url": "<string>",
        "expires_at": "2023-11-07T05:31:56Z",
        "duration": 123
      }
    ],
    "error": {
      "message": "<string>"
    }
  }
}