我想写一个嵌套的yaml文件。 类似于以下内容:

features:
      x: 103
      y: 166
      lbp: "no"
      depth: 
             cam1: "no"
             cam2: "yes"
             lidar: "yes"
      dim: 3

我有一个代码写简单的结构，但我不明白如何写嵌套与它。 我找到了一种读取嵌套YAML的方法:https://answers.opencv.org/question/93257/yml-file-reading-complex-structure/

但是似乎找不到如何编写嵌套的YAML。

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    const string out_fname = "/tmp/test.yaml";

    cout << "Write YAML file: " << out_fname << endl;
    cv::FileStorage opencv_file( out_fname, cv::FileStorage::WRITE);
    cv::Mat file_matrix;
    file_matrix = (cv::Mat_<int>(3, 3) << 1, 2, 3,
                                            3, 4, 6,
                                            7, 8, 9);
    opencv_file << "my_matrix" << file_matrix;

    opencv_file << "noise" << 43.3;
    opencv_file << "noise_type" << "Gaussian";
    opencv_file << "dim" << 3;

    // doesnt seem to work....!
    // opencv_file["feature"]["camera"] = 2.3;
    // opencv_file["feature"]["imu"] = 10;

    opencv_file.writeComment("a double value", 0);



    opencv_file.release();
}