fix: allow for reordered DD4hep_service geometry arguments

src/services/geometry/dd4hep/DD4hep_service.cc

@@ -31,10 +31,22 @@ DD4hep_service::~DD4hep_service(){
 /// Call Initialize if needed.
 //----------------------------------------------------------------
 dd4hep::Detector* DD4hep_service::detector() {
-    std::call_once( init_flag, &DD4hep_service::Initialize, this);
+    std::call_once(init_flag, &DD4hep_service::Initialize, this);
     return (m_dd4hepGeo);
 }
 
+//----------------------------------------------------------------
+// cellIDPositionConverter
+//
+/// Return pointer to the cellIDPositionConverter object.
+/// Call Initialize if needed.
+//----------------------------------------------------------------
+std::shared_ptr<const dd4hep::rec::CellIDPositionConverter>
+DD4hep_service::cellIDPositionConverter() {
+    std::call_once(init_flag, &DD4hep_service::Initialize, this);
+    return (m_cellid_converter);
+}
+
 //----------------------------------------------------------------
 // Initialize
 //

src/services/geometry/dd4hep/DD4hep_service.h

@@ -34,10 +34,7 @@ class DD4hep_service : public JService
     virtual ~DD4hep_service();
 
     virtual dd4hep::Detector* detector();
-    virtual std::shared_ptr<const dd4hep::rec::CellIDPositionConverter> cellIDPositionConverter() {
-        return m_cellid_converter;
-    }
-
+    virtual std::shared_ptr<const dd4hep::rec::CellIDPositionConverter> cellIDPositionConverter();
 protected:
     void Initialize();