How to use the aws-xray-sdk-core.resolveSegment function in aws-xray-sdk-core

function captureQuery() {
  var args = resolveArguments(arguments);
  var parent = AWSXRay.resolveSegment(args.segment);

  if (!parent) {
    AWSXRay.getLogger().info('Failed to capture Postgres. Cannot resolve sub/segment.');
    return this.__query.apply(this, arguments);
  }

  var subsegment = parent.addNewSubsegment(this.database + '@' + this.host);

  if (args.callback) {
    var cb = args.callback;

    if (AWSXRay.isAutomaticMode()) {
      args.callback = function autoContext(err, data) {
        var session = AWSXRay.getNamespace();

        session.run(function() {

return function close(err, req, res, next) {
      var segment = AWSXRay.resolveSegment(req.segment);

      if (segment && err) {
        segment.close(err);

        AWSXRay.getLogger().debug('Closed express segment with error: { url: ' + req.url + ', name: ' + segment.name + ', trace_id: ' +
          segment.trace_id + ', id: ' + segment.id + ', sampled: ' + !segment.notTraced + ' }');

      } else if (segment) {
        segment.close();

        AWSXRay.getLogger().debug('Closed express segment successfully: { url: ' + req.url + ', name: ' + segment.name + ', trace_id: ' +
          segment.trace_id + ', id: ' + segment.id + ', sampled: ' + !segment.notTraced + ' }');
      }

      if (next)
        next(err);

return function() {
    var args = resolveArguments(arguments);
    var parent = AWSXRay.resolveSegment(args.segment);
    var command;
    var originalOperation = this['__'+name];

    if (args.segment)
      delete arguments[arguments.length-1];

    if (!parent) {
      AWSXRay.getLogger().info('Failed to capture MySQL. Cannot resolve sub/segment.');
      return originalOperation.apply(this, arguments);
    }

    var config = this.config.connectionConfig || this.config;
    var subsegment = parent.addNewSubsegment(config.database + '@' + config.host);

    if (args.callback) {
      var cb = args.callback;