如何使用go in lambda安全地检查S3存储桶中是否存在文件？

package main

import (
    "context"
    "fmt"

    "github.com/aws/aws-lambda-go/lambda"
    "github.com/aws/aws-sdk-go/aws"
    "github.com/aws/aws-sdk-go/aws/session"
    "github.com/aws/aws-sdk-go/service/s3"
)

func handler(ctx context.Context) {
    // 创建一个新的会话
    sess := session.New()

    // 创建S3服务客户端
    svc := s3.New(sess)

    // 设置存储桶名称和前缀
    bucket := "your-bucket-name"
    prefix := "your-folder/"

    // 列出S3存储桶中的对象
    resp, err := svc.ListObjectsV2(&s3.ListObjectsV2Input{
        Bucket: aws.String(bucket),
        Prefix: aws.String(prefix),
    })

    if err != nil {
        fmt.Println("Error listing objects in S3 bucket:", err)
        return
    }

    // 检查返回的对象列表是否为空
    if len(resp.Contents) == 0 {
        fmt.Println("S3 bucket is empty")
    } else {
        fmt.Println("S3 bucket contains files")
    }
}

func main() {
    lambda.Start(handler)
}