Change the type for default_calendar to a string.
The type specified for the default calendar in the api docs wasn’t a valid type. The linting in the api docs repo reports:
`type` can be one of the following only: "object", "array", "string", "number", "integer", "boolean", "null".
This linting currently is only in the
Follow up to: cb5b0cb9d833345798dc93e9eaed6ac68c95e038