Write and read opencv3.0 ml files(random forest)

using namespace cv;using namespace std;int main(){    {        auto rtrees = cv::ml::RTrees::create();        rtrees->setMaxDepth(10);        rtrees->setMinSampleCount(2);        rtrees->setRegressionAccuracy(0);        rtrees->setUseSurrogates(false);        rtrees->setMaxCategories(16);        rtrees->setPriors(cv::Mat());        rtrees->setCalculateVarImportance(false);        rtrees->setActiveVarCount(0);        rtrees->setTermCriteria({ cv::TermCriteria::MAX_ITER, 100, 0 });        // Some dummy stuff here...        Mat1f feat(1, 5, 0.f);        Mat1f labels = (Mat1f(1, 5) << 1, 0, 1, 0, 1);        rtrees->train(feat, cv::ml::ROW_SAMPLE, labels);        rtrees->write(cv::FileStorage("smoke_classifier.xml",            cv::FileStorage::WRITE));    }    {        auto rtrees2 = cv::ml::RTrees::create();        cv::FileStorage read("smoke_classifier.xml", cv::FileStorage::READ);        rtrees2->read(read.root());        int a = rtrees2->getMinSampleCount();    }    return 0;}