diff --git a/common/gattlib_common.c b/common/gattlib_common.c
index f276e54..67f21ce 100644
--- a/common/gattlib_common.c
+++ b/common/gattlib_common.c
@@ -61,7 +61,7 @@ void gattlib_call_notification_handler(struct gattlib_handler *handler, const uu
 
 		d_gstate = PyGILState_Ensure();
 
-		PyObject *arglist = Py_BuildValue("(sIIO)", uuid_str, data, data_length, handler->user_data);
+		PyObject *arglist = Py_BuildValue("(sLIO)", uuid_str, data, data_length, handler->user_data);
 		PyEval_CallObject((PyObject *)handler->notification_handler, arglist);
 
 		PyGILState_Release(d_gstate);