Hi Richard.
You were spot on: this was the issue.
Thank you so much for your answer and for CodeRunner, it's really adding a lot of value to Moodle.
Joël.
Developers' Forum
Running Pandas (Python3) with Jobe
This forum has a limit to the number of forum postings you can make in a given time period - this is currently set at 5 posting(s) in 1 day