removed superfluous return

src/storm/models/sparse/StateLabeling.cpp

@@ -50,7 +50,7 @@ namespace storm {
             }
             
             void StateLabeling::addLabelToState(std::string const& label, storm::storage::sparse::state_type state) {
-                return ItemLabeling::addLabelToItem(label, state);
+                ItemLabeling::addLabelToItem(label, state);
             }
             
             bool StateLabeling::getStateHasLabel(std::string const& label, storm::storage::sparse::state_type state) const {