How to use the google-gax.lro function in google-gax

var protoFilesRoot = new gax.grpc.GoogleProtoFilesRoot();
    protoFilesRoot = protobuf.loadSync(
      path.join(
        __dirname,
        '..',
        '..',
        'protos',
        'google/privacy/dlp/v2beta1/dlp.proto'
      ),
      protoFilesRoot
    );

    // This API contains "long-running operations", which return a
    // an Operation object that allows for tracking of the operation,
    // rather than holding a request open.
    this.operationsClient = new gax.lro({
      auth: gaxGrpc.auth,
      grpc: gaxGrpc.grpc,
    }).operationsClient(opts);

    var analyzeDataSourceRiskResponse = protoFilesRoot.lookup(
      'google.privacy.dlp.v2beta1.RiskAnalysisOperationResult'
    );
    var analyzeDataSourceRiskMetadata = protoFilesRoot.lookup(
      'google.privacy.dlp.v2beta1.RiskAnalysisOperationMetadata'
    );
    var createInspectOperationResponse = protoFilesRoot.lookup(
      'google.privacy.dlp.v2beta1.InspectOperationResult'
    );
    var createInspectOperationMetadata = protoFilesRoot.lookup(
      'google.privacy.dlp.v2beta1.InspectOperationMetadata'
    );

}, opts);

  var googleApiClient = [
    'gl-node/' + process.versions.node
  ];
  if (opts.libName && opts.libVersion) {
    googleApiClient.push(opts.libName + '/' + opts.libVersion);
  }
  googleApiClient.push(
    CODE_GEN_NAME_VERSION,
    'gax/' + gax.version,
    'grpc/' + gaxGrpc.grpcVersion
  );


  this.operationsClient = new gax.lro({
    auth: gaxGrpc.auth,
    grpc: gaxGrpc.grpc
  }).operationsClient(opts);

  this.longrunningDescriptors = {
    createInstance: new gax.LongrunningDescriptor(
      this.operationsClient,
      grpcClients.google.spanner.admin.instance.v1.Instance.decode,
      grpcClients.google.spanner.admin.instance.v1.CreateInstanceMetadata.decode),
    updateInstance: new gax.LongrunningDescriptor(
      this.operationsClient,
      grpcClients.google.spanner.admin.instance.v1.Instance.decode,
      grpcClients.google.spanner.admin.instance.v1.UpdateInstanceMetadata.decode)
  };

  var defaults = gaxGrpc.constructSettings(

}, opts);

  var googleApiClient = [
    'gl-node/' + process.versions.node
  ];
  if (opts.libName && opts.libVersion) {
    googleApiClient.push(opts.libName + '/' + opts.libVersion);
  }
  googleApiClient.push(
    CODE_GEN_NAME_VERSION,
    'gax/' + gax.version,
    'grpc/' + gaxGrpc.grpcVersion
  );


  this.operationsClient = new gax.lro({
    auth: gaxGrpc.auth,
    grpc: gaxGrpc.grpc
  }).operationsClient(opts);

  this.longrunningDescriptors = {
    createDatabase: new gax.LongrunningDescriptor(
      this.operationsClient,
      grpcClients.google.spanner.admin.database.v1.Database.decode,
      grpcClients.google.spanner.admin.database.v1.CreateDatabaseMetadata.decode),
    updateDatabaseDdl: new gax.LongrunningDescriptor(
      this.operationsClient,
      grpcClients.google.protobuf.Empty.decode,
      grpcClients.google.spanner.admin.database.v1.UpdateDatabaseDdlMetadata.decode)
  };

  var defaults = gaxGrpc.constructSettings(