Python box selection not working

Hello, I’m using Python 3.10 to build my program. For the control style, I override the vtkInteractorStyleRubberBandPick class. Next, I want to be able to frame the actors in the scene and get the id of the selected cells. As an example, I use examples from the vtk website. But, unfortunately, this line frustum = self.GetInteractor().GetPicker().GetFrustum() gives me an error. Could you help?