Who can download data? Course owners or group owners? Not entirely clear.
Not possible to get the resource-id in the step before calling this function. Not a major issue for us, since we only have one course, but this seems to be a "bug" in the opal API. It gets the ID of the course twice, but not the resource id.
Let's keep this open until clarification from Opal.
We might want to change:
[x] get_course_results has parameter course_id; this is actually the resource id, could be confusing
[x] return value could be the full path of data to ease reading it in in the next step
This would be useful to analyze results programmatically.