model to dot string

src/storage/model.cpp

@@ -230,6 +230,7 @@ void define_sparse_model(py::module& m) {
         .def_property_readonly("backward_transition_matrix", &SparseModel<RationalFunction>::getBackwardTransitions, py::return_value_policy::reference, py::keep_alive<1, 0>(), "Backward transition matrix")
         .def("reduce_to_state_based_rewards", &SparseModel<RationalFunction>::reduceToStateBasedRewards)
         .def("__str__", getModelInfoPrinter<RationalFunction>("ParametricModel"))
+        .def("to_dot", [](SparseModel<RationalFunction>& model) { std::stringstream ss; model.writeDotToStream(ss); return ss.str(); }, "Write dot to a string")
     ;
 
     py::class_<SparseDtmc<RationalFunction>, std::shared_ptr<SparseDtmc<RationalFunction>>>(m, "SparseParametricDtmc", "pDTMC in sparse representation", modelRatFunc)