autodesk forge – BIM360 Create New Project parameters

I am writing an application that will automate the creation of BIM360 projects using this API endpiont. There are some required parameters and optional parameters to the endpoint. I see that parameters such as country and state_or_province are optional but there is a list of enums provided.

1. Since these parameters are optional can these inputs be left blank / null? If so will the endpoint return an error?
2. If a value is provided, do these parameters have to confirm to the enum list or will the endpoint return an error if the inputs are not as stated in the enum list?

The API documentation is unclear and unfortunately I cannot test this, as each test would require creating a new BIM360 project and this would clutter our Hub.