FatrasG4Tool Node1 FatrasG4Tool   + FatrasG4Tool() # makeFastSimModel() Node2 FastSimulationBase # m_regionName # m_noRegions + FastSimulationBase() + initializeFastSim() + BeginOfAthenaEvent() + EndOfAthenaEvent() # getRegion() Node2->Node1 Node3 extends< AthAlgTool, IFastSimulation >     Node3->Node2