Interaction constraints in sklearn API (python)

in the training API, I can set/unset the interaction constraints for a training step by a parameter of the train method.

In the sklearn API, interaction constraints is an attribute of the XGBRegressor object and not passable with the fit method.

So do I change it per training step by setting it with the regressor object?
If I do not want to have any interaction constraints, do I set it to None?

Thank you very much!