Construct nuSTORM from a GDML file

def Construct(self):  # pylint: disable-msg=C0103
        """Construct nuSTORM from a GDML file"""
        # Parse the GDML
        self.world = self.gdml_parser.GetWorldVolume()

        # Create sensitive detector
        self.sensitive_detector = ScintSD()

        # Get logical volume for X view, then attach SD
        my_lv = G4.G4LogicalVolumeStore.GetInstance().GetVolumeID(1)
        assert my_lv.GetName() == "ScintillatorBarX"
        my_lv.SetSensitiveDetector(self.sensitive_detector)

        # Get logical volume for Y view, then attach SD
        my_lv = G4.G4LogicalVolumeStore.GetInstance().GetVolumeID(2)
        assert my_lv.GetName() == "ScintillatorBarY"
        my_lv.SetSensitiveDetector(self.sensitive_detector)

        my_lv = G4.G4LogicalVolumeStore.GetInstance().GetVolumeID(0)
        assert my_lv.GetName() == "SteelPlane"

        # field
        self.field_manager = G4.G4FieldManager()
        self.my_field = MagneticField.WandsToroidField(self.field_polarity)
        self.field_manager.SetDetectorField(self.my_field)
        self.field_manager.CreateChordFinder(self.my_field)
        my_lv.SetFieldManager(self.field_manager, False)

        self.log.info("Materials:")
        self.log.info(G4.G4Material.GetMaterialTable())

        # Return pointer to world volume
        return self.world