diff --git a/src/runner/pythonrunner.cpp b/src/runner/pythonrunner.cpp
index 011fc04..0c6b1f6 100644
--- a/src/runner/pythonrunner.cpp
+++ b/src/runner/pythonrunner.cpp
@@ -558,7 +558,7 @@ BOOST_PYTHON_MODULE(mobase)
 
   bpy::class_<MOBase::GuessedValue<QString>, boost::noncopyable>("GuessedString")
       .def(bpy::init<>())
-      .def(bpy::init<QString const&, EGuessQuality>())
+      .def(bpy::init<QString const&, EGuessQuality>((bpy::arg("value"), "quality")))
       .def("update",
            static_cast<GuessedValue<QString>& (GuessedValue<QString>::*)(const QString&)>(&GuessedValue<QString>::update),
            bpy::return_self<>(), bpy::arg("value"))