How to add contentInset to scrollview / collectionview / calendar?

[Sebastiaan de Weert]

How can I add a contentInset to the calendar view?

I want to have an inset on the left and right sides.

Now, when I do this with constraints and I scroll the page, the calendar is cut off at the edge. I want to use contentInset to eliminate this edge and make the swipe smoother, utilizing the full-screen edges.

I tried this code, but it's not working:
self.calendar.collectionView.contentInset = UIEdgeInsets(top: 0.0, left: 40.0, bottom: 0.0, right: 40.0)

My calendar right now with constraint:

What I would like to achieve:

Thanks!!