transformation: default no formulae given

src/core/transformation.cpp

@@ -3,6 +3,6 @@
 
 void define_transformation(py::module& m) {
     // Transform model
-    m.def("_transform_to_sparse_model", &storm::api::transformSymbolicToSparseModel<storm::dd::DdType::Sylvan, double>, "Transform symbolic model into sparse model", py::arg("model"), py::arg("formulae"));
-    m.def("_transform_to_sparse_parametric_model", &storm::api::transformSymbolicToSparseModel<storm::dd::DdType::Sylvan, storm::RationalFunction>, "Transform symbolic parametric model into sparse parametric model", py::arg("model"), py::arg("formulae"));
+    m.def("_transform_to_sparse_model", &storm::api::transformSymbolicToSparseModel<storm::dd::DdType::Sylvan, double>, "Transform symbolic model into sparse model", py::arg("model"), py::arg("formulae") = std::vector<std::shared_ptr<storm::logic::Formula const>>());
+    m.def("_transform_to_sparse_parametric_model", &storm::api::transformSymbolicToSparseModel<storm::dd::DdType::Sylvan, storm::RationalFunction>, "Transform symbolic parametric model into sparse parametric model", py::arg("model"), py::arg("formulae") = std::vector<std::shared_ptr<storm::logic::Formula const>>());
 }