Using FabricRestClient To Make Fabric REST API Calls

Awesome post.

Can I ask how do the POST requests work with FabricRestClient? I'm trying to invoke Job scheduler APIs to invoke an item job instance as covered in below REST API doc.

"Job Scheduler - Run On Demand Item Job" (Can't post links as I'm restricted currently)

I tried this: response = client.post(f"v1/workspaces/{workspaceId}/items/{itemId}/jobs/instances?jobType={jobType}")

But I'm getting this exception FabricHTTPException: 400 Bad Request for url: . . . "moreDetails":[{"errorCode":"InvalidParameter","message":"'runOnDemandItemJobRequest' is a required parameter"}],"message":"The request has an invalid input"}

I understand that as per the doc, there's a request body that must go along too but can't figure out where to put that in the request method. Would appreciate any help on this. Thanks!