WIP.
diff --git a/python/repeated.h b/python/repeated.h
index 06945bf..9e8530b 100644
--- a/python/repeated.h
+++ b/python/repeated.h
@@ -49,6 +49,9 @@
// Reifies a repeated field stub to point to the concrete data in `arr`.
void PyUpb_RepeatedContainer_Reify(PyObject* self, upb_array* arr);
+// Reifies this repeated object if it is not already reified.
+upb_array* PyUpb_RepeatedContainer_EnsureReified(PyObject* self);
+
// Implements repeated_field.extend(iterable). `_self` must be a repeated
// field (either repeated composite or repeated scalar).
PyObject* PyUpb_RepeatedContainer_Extend(PyObject* _self, PyObject* value);
