diff -r 7ec1cfe19a24 -r a4137aedcb3a include/dolfinx_access/nanobind_helpers.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/dolfinx_access/nanobind_helpers.h	Thu Feb 26 09:32:12 2026 -0500
@@ -0,0 +1,25 @@
+#pragma once
+#include <cmath>
+
+#pragma once
+#include <dolfinx/fem/Function.h>
+
+#pragma once
+#include <Python.h>
+
+namespace dolfinx_access {
+    using namespace dolfinx::fem;
+
+    using PyObject = ::PyObject;
+    typedef Function<double> Function_f64;
+
+    const Function_f64* cast_Function_f64(const PyObject* obj);
+    Function_f64* cast_mut_Function_f64(PyObject* obj);
+
+    bool check_Function_f64(const PyObject* obj);
+
+    PyObject* wrap_Function_f64(Function_f64* f);
+
+} // namespace dolfinx_access
+
+extern "C" PyObject* PyInit_dolfinx_access();