Bulk actions on the contribution list view

Thanks to @kolodzie 's reply to Number of reviews by each reviewer and with some trial and error, I have now figured out how to select the contributions I want via Indico shell. Not being much good with Python, I can’t figure out how to carry out a change on the contributions listed.

Contribution.query.filter(Contribution.type_id == <id of the contribution type>).all()

I can see that there is a “duration” option in the API for Contributions but I can’t figure out how to see it and set it using Indico shell.

Thanks,
Ying