diff --git a/src/python3/cpp_etc.cpp b/src/python3/cpp_etc.cpp
index 93c8fb22f..409acb097 100644
--- a/src/python3/cpp_etc.cpp
+++ b/src/python3/cpp_etc.cpp
@@ -41,9 +41,8 @@ PYBIND11_MODULE(cpp_etc, m)
     auto samrai_restart_file = [](std::string path) {
         return PHARE::amr::HierarchyRestarter::getRestartFileFullPath(path);
     };
-    py::class_<core::Span<double>, std::shared_ptr<core::Span<double>>>(m, "Span");
-    py::class_<PyArrayWrapper<double>, std::shared_ptr<PyArrayWrapper<double>>, core::Span<double>>(
-        m, "PyWrapper");
+    py::class_<core::Span<double>, py::smart_holder>(m, "Span");
+    py::class_<PyArrayWrapper<double>, py::smart_holder, core::Span<double>>(m, "PyWrapper");
 
     m.def("makePyArrayWrapper", makePyArrayWrapper<double>);
 
diff --git a/src/python3/cpp_simulator.cpp b/src/python3/cpp_simulator.cpp
index a5c0a5d1c..cf20c4666 100644
--- a/src/python3/cpp_simulator.cpp
+++ b/src/python3/cpp_simulator.cpp
@@ -9,8 +9,13 @@ namespace py = pybind11;
 
 namespace PHARE::pydata
 {
+
 PYBIND11_MODULE(PHARE_CPP_MOD_NAME, m)
 {
+    declarePatchData<std::vector<double>, 1>(m, "PatchDataVectorDouble_1D");
+    declarePatchData<std::vector<double>, 2>(m, "PatchDataVectorDouble_2D");
+    declarePatchData<std::vector<double>, 3>(m, "PatchDataVectorDouble_3D");
+
     declare_essential(m);
 
     declareDim<1>(m);
@@ -18,9 +23,6 @@ PYBIND11_MODULE(PHARE_CPP_MOD_NAME, m)
     declareDim<3>(m);
 
     core::apply(core::possibleSimulators(), [&](auto const& simType) { declare_all(m, simType); });
-
-    declarePatchData<std::vector<double>, 1>(m, "PatchDataVectorDouble_1D");
-    declarePatchData<std::vector<double>, 2>(m, "PatchDataVectorDouble_2D");
-    declarePatchData<std::vector<double>, 3>(m, "PatchDataVectorDouble_3D");
 }
+
 } // namespace PHARE::pydata
diff --git a/src/python3/cpp_simulator.hpp b/src/python3/cpp_simulator.hpp
index 47a9e6166..6fd1b80d0 100644
--- a/src/python3/cpp_simulator.hpp
+++ b/src/python3/cpp_simulator.hpp
@@ -32,7 +32,7 @@ template<typename Type, std::size_t dimension>
 void declarePatchData(py::module& m, std::string key)
 {
     using PatchDataType = PatchData<Type, dimension>;
-    py::class_<PatchDataType>(m, key.c_str())
+    py::class_<PatchDataType, py::smart_holder>(m, key.c_str())
         .def_readonly("patchID", &PatchDataType::patchID)
         .def_readonly("origin", &PatchDataType::origin)
         .def_readonly("lower", &PatchDataType::lower)
@@ -46,7 +46,7 @@ void declareDim(py::module& m)
 {
     using CP         = core::ContiguousParticles<dim>;
     std::string name = "ContiguousParticles_" + std::to_string(dim);
-    py::class_<CP, std::shared_ptr<CP>>(m, name.c_str())
+    py::class_<CP, py::smart_holder>(m, name.c_str())
         .def(py::init<std::size_t>())
         .def_readwrite("iCell", &CP::iCell)
         .def_readwrite("delta", &CP::delta)
@@ -88,7 +88,7 @@ void declare_etc(py::module& m)
     using Sim        = Simulator<opts>;
     using DW         = DataWrangler<opts>;
     std::string name = "DataWrangler" + type_string;
-    py::class_<DW, std::shared_ptr<DW>>(m, name.c_str())
+    py::class_<DW, py::smart_holder>(m, name.c_str())
         .def(py::init<std::shared_ptr<Sim> const&, std::shared_ptr<amr::Hierarchy> const&>())
         .def(py::init<std::shared_ptr<ISimulator> const&, std::shared_ptr<amr::Hierarchy> const&>())
         .def("sync_merge", &DW::sync_merge)
@@ -97,8 +97,7 @@ void declare_etc(py::module& m)
 
     using PL = PatchLevel<opts>;
     name     = "PatchLevel_" + type_string;
-
-    py::class_<PL, std::shared_ptr<PL>>(m, name.c_str())
+    py::class_<PL, py::smart_holder>(m, name.c_str())
         .def("getEM", &PL::getEM)
         .def("getE", &PL::getE)
         .def("getB", &PL::getB)
@@ -123,7 +122,7 @@ void declare_etc(py::module& m)
     using _Splitter
         = PHARE::amr::Splitter<_dim, _interp, core::RefinedParticlesConst<nbRefinedPart>>;
     name = "Splitter" + type_string;
-    py::class_<_Splitter, std::shared_ptr<_Splitter>>(m, name.c_str())
+    py::class_<_Splitter, py::smart_holder>(m, name.c_str())
         .def(py::init<>())
         .def_property_readonly_static("weight", [](py::object) { return _Splitter::weight; })
         .def_property_readonly_static("delta", [](py::object) { return _Splitter::delta; });
@@ -146,7 +145,7 @@ void declare_sim(py::module& m)
     using Sim        = Simulator<opts>;
     std::string name = "Simulator" + type_string;
     declareSimulator<Sim>(
-        py::class_<Sim, std::shared_ptr<Sim>>(m, name.c_str())
+        py::class_<Sim, py::smart_holder>(m, name.c_str())
             .def_property_readonly_static("dims", [](py::object) { return Sim::dimension; })
             .def_property_readonly_static("interp_order",
                                           [](py::object) { return Sim::interp_order; })
@@ -182,11 +181,11 @@ void declare_all(py::module& m, std::tuple<Dimension, InterpOrder, NbRefinedPart
 
 void inline declare_essential(py::module& m)
 {
-    py::class_<SamraiLifeCycle, std::shared_ptr<SamraiLifeCycle>>(m, "SamraiLifeCycle")
+    py::class_<SamraiLifeCycle, py::smart_holder>(m, "SamraiLifeCycle")
         .def(py::init<>())
         .def("reset", &SamraiLifeCycle::reset);
 
-    py::class_<PHARE::amr::Hierarchy, std::shared_ptr<PHARE::amr::Hierarchy>>(m, "AMRHierarchy");
+    py::class_<PHARE::amr::Hierarchy, py::smart_holder>(m, "AMRHierarchy");
     m.def("make_hierarchy", []() { return PHARE::amr::Hierarchy::make(); });
 
     m.def("mpi_size", []() { return core::mpi::size(); });
diff --git a/src/python3/patch_data.hpp b/src/python3/patch_data.hpp
index cb289c514..e87477e29 100644
--- a/src/python3/patch_data.hpp
+++ b/src/python3/patch_data.hpp
@@ -25,7 +25,8 @@ struct __attribute__((visibility("hidden"))) PatchData
 
     template<typename... Args>
     PatchData(Args&&... args)
-        : data{std::forward<Args...>(args...)}
+        requires std::is_constructible_v<Data, Args&&...>
+        : data{std::forward<Args>(args)...}
     {
     }
 };