diff --git a/src/helpers.h b/src/helpers.h
index ffda72c..0635ef6 100644
--- a/src/helpers.h
+++ b/src/helpers.h
@@ -16,12 +16,23 @@
  * Used for __str__ functions.
  */
 template<typename T>
-std::string streamToString(T const & t) {
+std::string streamToString(T const& t) {
     std::stringstream ss;
     ss << t;
     return ss.str();
 }
 
+template<typename T>
+std::string containerToString(T& t) {
+    // is there a way to make ^this const&?
+    // I guess not all containers have const iterators
+    std::stringstream ss;
+    for (auto const& e : t) {
+        ss << e << ", ";
+    }
+    return ss.str();
+}
+
 // Be warned: Enabling something like this will break everything about Monomial,
 // as to Python the shared_ptr (Arg) IS the Monomial
 //  //PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>);
diff --git a/src/storage/matrix.cpp b/src/storage/matrix.cpp
index 39149f8..1d03384 100644
--- a/src/storage/matrix.cpp
+++ b/src/storage/matrix.cpp
@@ -122,25 +122,13 @@ void define_sparse_matrix(py::module& m) {
         .def("__iter__", [](storm::storage::SparseMatrix<double>::rows& rows) {
                 return py::make_iterator(rows.begin(), rows.end());
             }, py::keep_alive<0, 1>())
-        .def("__str__", [](storm::storage::SparseMatrix<double>::const_rows& rows) {
-                std::stringstream stream;
-                for (auto transition : rows) {
-                    stream << transition << ", ";
-                }
-                return stream.str();
-            })
+        .def("__str__", &containerToString<storm::storage::SparseMatrix<double>::rows>)
     ;
 
     py::class_<storm::storage::SparseMatrix<storm::RationalFunction>::rows>(m, "ParametricSparseMatrixRows", "Set of rows in a parametric sparse matrix")
         .def("__iter__", [](storm::storage::SparseMatrix<storm::RationalFunction>::rows& rows) {
                 return py::make_iterator(rows.begin(), rows.end());
             }, py::keep_alive<0, 1>())
-        .def("__str__", [](storm::storage::SparseMatrix<storm::RationalFunction>::const_rows& rows) {
-                std::stringstream stream;
-                for (auto transition : rows) {
-                    stream << transition << ", ";
-                }
-                return stream.str();
-            })
+        .def("__str__", &containerToString<storm::storage::SparseMatrix<storm::RationalFunction>::rows>)
     ;
 }