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: handleServiceErrorCodes.go
    path of file: ./repos/aws-doc-sdk-examples/go/example_code/extending_sdk
    
    the code of the file until where you have to start completion: // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

package main

import (
	"fmt"
	"os"
	"path/filepath"

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

func exitErrorf(msg string, args ...interface{}) {
	fmt.Fprintf(os.Stderr, msg+"\n", args...)
	os.Exit(1)
}

// Will make a request to 
    
func main() {
	if len(os.Args) < 3 {
		exitErrorf("Usage: %s <bucket> <key>", filepath.Base(os.Args[0]))
	}
	sess := session.Must(session.NewSession())

	svc := s3.New(sess)
	resp, err := svc.GetObject(&s3.GetObjectInput{
		Bucket: aws.String(os.Args[1]),
		Key:    aws.String(os.Args[2]),
	})

	if err != nil {
		// Casting to the awserr.Error type will allow you to inspect the error
		// code returned by the service in code. The error code can be used
		// to switch on context specific functionality. In this case a context
		// specific error message is printed to the user based on the bucket
		// and key existing.
		//
		// For information on other S3 API error codes see:
		// http://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html
		if aerr, ok := err.(awserr.Error); ok {
			switch aerr.Code() {
			case s3.ErrCodeNoSuchBucket:
				exitErrorf("bucket %s does not exist", os.Args[1])
			case s3.ErrCodeNoSuchKey:
				exitErrorf("object with key %s does not exist in bucket %s", os.Args[2], os.Args[1])
			}
		}
		exitErrorf("unknown error occurred, %v", err)
	}
	defer resp.Body.Close()

	fmt.Printf("s3://%s/%s exists. size: %d\n", os.Args[1], os.Args[2],
		aws.Int64Value(resp.ContentLength))
}