diff --git a/include/podio/detail/Pythonizations.h b/include/podio/detail/Pythonizations.h
index fb498750d..b8661eace 100644
--- a/include/podio/detail/Pythonizations.h
+++ b/include/podio/detail/Pythonizations.h
@@ -3,58 +3,17 @@
 
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
-#include <stdexcept>
 #include <string>
 
 namespace podio::detail::pythonizations {
 
 // Callback function for the subscript pythonization
 // Calls the `at` method and change exception type to IndexError if the index is out of range
-static inline PyObject* subscript(PyObject* self, PyObject* index) {
-  PyObject* result = PyObject_CallMethod(self, "at", "O", index);
-  if (!result) {
-    PyObject* exc = PyErr_Occurred();
-    // Check if the exception is `cppyy.gbl.std.out_of_range`
-    // Since PyImport_ImportModule("cppyy") fails, this workaround checks the exception name
-    if (exc && PyObject_HasAttrString(exc, "__name__")) {
-      PyObject* exc_name = PyObject_GetAttrString(exc, "__name__");
-      if (exc_name) {
-        const char* name_cstr = PyUnicode_AsUTF8(exc_name);
-        if (name_cstr && strcmp(name_cstr, "out_of_range") == 0) {
-          PyErr_Clear();
-          PyErr_SetString(PyExc_IndexError, "Index out of range");
-        }
-        Py_DECREF(exc_name);
-      }
-    }
-  }
-  return result;
-}
+PyObject* subscript(PyObject* self, PyObject* index);
 
 // Helper to register the subscript pythonization callback as `__getitem__` method
-static inline void pythonize_subscript(PyObject* klass, const std::string& name) {
-  static PyMethodDef ml = {"subscipt_pythonization", subscript, METH_VARARGS, R"(
-        Raise an `IndexError` exception if an index is invalid.
-        The `__getitem__` will return immutable datatype objects instead of the mutable ones.
-  )"};
-  auto* func = PyCFunction_New(&ml, klass);
-  if (!func) {
-    throw std::runtime_error("Failed to create Python subscript function for class " + name);
-  }
-  auto* method = PyInstanceMethod_New(func);
-  if (!method) {
-    Py_DECREF(func);
-    throw std::runtime_error("Failed to create Python instance method for subscript for class " + name);
-  }
-  if (0 != PyObject_SetAttrString(klass, "__getitem__", method)) {
-    Py_DECREF(method);
-    Py_DECREF(func);
-    throw std::runtime_error("Failed to set __getitem__ attribute on class " + name);
-  }
-  Py_DECREF(func);
-  Py_DECREF(method);
-}
+void pythonize_subscript(PyObject* klass, const std::string& name);
 
 } // namespace podio::detail::pythonizations
 
-#endif // PODIO_DETAIL_PYTHONIZATIONS_H
+#endif // PODIO_DETAIL_PYTHONIZATIONS_H
\ No newline at end of file
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 260163ed1..2d2d312c7 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -61,6 +61,7 @@ SET(core_sources
   MurmurHash3.cpp
   SchemaEvolution.cc
   Glob.cc
+  Pythonizations.cc
   )
 
 SET(core_headers
@@ -79,6 +80,7 @@ SET(core_headers
 
 PODIO_ADD_LIB_AND_DICT(podio "${core_headers}" "${core_sources}" selection.xml)
 target_compile_options(podio PRIVATE -pthread)
+target_link_libraries(podio PRIVATE Python3::Python)
 # For Frame.h
 if (ROOT_VERSION VERSION_LESS 6.36)
   target_compile_definitions(podio PUBLIC PODIO_ROOT_OLDER_6_36=1)
diff --git a/src/Pythonizations.cc b/src/Pythonizations.cc
new file mode 100644
index 000000000..5602dc016
--- /dev/null
+++ b/src/Pythonizations.cc
@@ -0,0 +1,55 @@
+#include "podio/detail/Pythonizations.h"
+
+#include <cstring>
+#include <stdexcept>
+
+namespace podio::detail::pythonizations {
+
+// Callback function for the subscript pythonization
+// Calls the `at` method and change exception type to IndexError if the index is out of range
+PyObject* subscript(PyObject* self, PyObject* index) {
+  PyObject* result = PyObject_CallMethod(self, "at", "O", index);
+  if (!result) {
+    PyObject* exc = PyErr_Occurred();
+    // Check if the exception is `cppyy.gbl.std.out_of_range`
+    // Since PyImport_ImportModule("cppyy") fails, this workaround checks the exception name
+    if (exc && PyObject_HasAttrString(exc, "__name__")) {
+      PyObject* exc_name = PyObject_GetAttrString(exc, "__name__");
+      if (exc_name) {
+        const char* name_cstr = PyUnicode_AsUTF8(exc_name);
+        if (name_cstr && strcmp(name_cstr, "out_of_range") == 0) {
+          PyErr_Clear();
+          PyErr_SetString(PyExc_IndexError, "Index out of range");
+        }
+        Py_DECREF(exc_name);
+      }
+    }
+  }
+  return result;
+}
+
+// Helper to register the subscript pythonization callback as `__getitem__` method
+void pythonize_subscript(PyObject* klass, const std::string& name) {
+  static PyMethodDef ml = {"subscript_pythonization", subscript, METH_VARARGS, R"(
+        Raise an `IndexError` exception if an index is invalid.
+        The `__getitem__` will return immutable datatype objects instead of the mutable ones.
+  )"};
+  auto* func = PyCFunction_New(&ml, klass);
+  if (!func) {
+    throw std::runtime_error("Failed to create Python subscript function for class " + name);
+  }
+  auto* method = PyInstanceMethod_New(func);
+  if (!method) {
+    Py_DECREF(func);
+    throw std::runtime_error("Failed to create Python instance method for subscript for class " + name);
+  }
+  if (0 != PyObject_SetAttrString(klass, "__getitem__", method)) {
+    Py_DECREF(method);
+    Py_DECREF(func);
+    throw std::runtime_error("Failed to set __getitem__ attribute on class " + name);
+  }
+  Py_DECREF(func);
+  Py_DECREF(method);
+}
+
+} // namespace podio::detail::pythonizations
\ No newline at end of file