Implementation of the G4hImpactIonisation class models low energy

Hello friends, I am trying to implement the G4hBetheBloch model that belongs to the G4hImpactIonisation class, the problem is that I don’t know how to add the G4hBetheBloch model to the G4hImpactIonisation constructor. I leave the code used, thank you very much
Captura de pantalla 2021-04-21 a las 1.13.59 a.m.