How to forcefully set the previously saved state of metrics in the prom-client registry?

Question

My node.js application uses prom-client. Once a minute, I save the current metrics to the database as a string. How to install them in the registry back from the string?

async function saveMetricsToDatabase(dbSuite, register) {
  try {
    const metrics = register.metrics();
    const { metricsMapper } = dbSuite;
    await metricsMapper.create({ data: metrics }); // save into database
  } catch (err) {
    console.error('Failed to save metrics to database:', err);
  }
}

async function loadMetricsFromDatabase(dbSuite, register) {
  try {
    const { metricsMapper } = dbSuite;
    const result = await metricsMapper.findOne({
      order: [['createdAt', 'DESC']],
    });
    if (result) {
      const metrics = result.data;
      register.clear();

      register.xxx(metrics); // In the metrics variable, the past state of the metrics. 
                             // How to install them in the current registry?
    }
  } catch (err) {
    console.error('Failed to load metrics from database:', err);
  }
}

Didn't find the preferred method in the technical documentation. Writing to the database is correct. https://github.com/siimon/prom-client