func (s *BucketService) IsExist(ctx context.Context) (isExist bool, err error)

package main

import (
        "context"
        "fmt"
        "github.com/tencentyun/cos-go-sdk-v5"
        "net/http"
        "net/url"
        "os"
)

func main(){
        // Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
        // Replace it with your region, which can be viewed in the COS console at https://console.tencentcloud.com/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224.
        u, _ := url.Parse("https://examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com")
        b := &cos.BaseURL{BucketURL: u}
        client := cos.NewClient(b, &http.Client{
                Transport: &cos.AuthorizationTransport{
                        // Get the key from environment variables
                        // Environment variable `SECRETID` refers to the user's `SecretId`, which can be viewed in the CAM console at https://console.tencentcloud.com/cam/capi.
                        SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
                        // Environment variable `SECRETKEY` refers to the user's `SecretKey`, which can be viewed in the CAM console at https://console.tencentcloud.com/cam/capi.
                        SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit  https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
                },
        })

        ok, err := client.Bucket.IsExist(context.Background())
        if err == nil && ok {
                fmt.Printf("bucket exists\\n")
        } else if err != nil {
                fmt.Printf("head bucket failed: %v\\n", err)
        } else {
                fmt.Printf("bucket does not exist\\n")
        }
}