Interval and frequency required for trial period

{
  "error": {
    "type": "request_error",
    "code": "price_trial_period_missing_fields",
    "detail": "`trial_period` requires both `interval` and `frequency` to be set.",
    "documentation_url": "https://developer.paddle.com/errors/prices/price_trial_period_missing_fields"
  },
  "meta": {
    "request_id": "00000000-0000-0000-0000-000000000000"
  }
}