You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spanner_ha.go
    path of file: ./repos/vault/physical/spanner
    
    the code of the file until where you have to start completion: // Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: BUSL-1.1

package spanner

import (
	"context"
	"fmt"
	"sync"
	"time"

	"cloud.google.com/go/spanner"
	metrics "github.com/armon/go-metrics"
	uuid "github.com/hashicorp/go-uuid"
	"github.com/hashicorp/vault/sdk/physical"
	"github.com/pkg/errors"
	"google.golang.org/grpc/codes"
)

// Verify Backend satisfies the correct interfaces
var (
	_ physical.HABackend = (*Backend)(n
    
func (l *Lock) get(ctx context.Context) (*LockRecord, error) {
	// Read
	row, err := l.backend.haClient.Single().ReadRow(ctx, l.backend.haTable, spanner.Key{l.key}, []string{"Key", "Value", "Timestamp", "Identity"})
	if spanner.ErrCode(err) == codes.NotFound {
		return nil, nil
	}
	if err != nil {
		return nil, fmt.Errorf("failed to read value for %q: %w", l.key, err)
	}

	var r LockRecord
	if err := row.ToStruct(&r); err != nil {
		return nil, fmt.Errorf("failed to decode lock: %w", err)
	}
	return &r, nil
}