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: SnsSubscribe.go
    path of file: ./repos/aws-doc-sdk-examples/go/example_code/sns
    
    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
// snippet-start:[sns.go.subscribe]
package main

import (
	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/sns"

	"flag"
	"fmt"
	"os"
)

func main() {
	emailPtr := flag.String("e", "", "The email address of the user subscribing to the topic")
	topicPtr := flag.String("t", "", "The ARN of the topic to which the user subscribes")

	flag.Parse()

	if *emailPtr == "" || *topicPtr == "" {
		fmt.Println("You must supply an email address and topic ARN")
		fmt.Println("Usage: go run SnsSubscribe.go -e EMAI
    
func main() {
	emailPtr := flag.String("e", "", "The email address of the user subscribing to the topic")
	topicPtr := flag.String("t", "", "The ARN of the topic to which the user subscribes")

	flag.Parse()

	if *emailPtr == "" || *topicPtr == "" {
		fmt.Println("You must supply an email address and topic ARN")
		fmt.Println("Usage: go run SnsSubscribe.go -e EMAIL -t TOPIC-ARN")
		os.Exit(1)
	}

	// Initialize a session that the SDK will use to load
	// credentials from the shared credentials file. (~/.aws/credentials).
	sess := session.Must(session.NewSessionWithOptions(session.Options{
		SharedConfigState: session.SharedConfigEnable,
	}))

	svc := sns.New(sess)

	result, err := svc.Subscribe(&sns.SubscribeInput{
		Endpoint:              emailPtr,
		Protocol:              aws.String("email"),
		ReturnSubscriptionArn: aws.Bool(true), // Return the ARN, even if user has yet to confirm
		TopicArn:              topicPtr,
	})
	if err != nil {
		fmt.Println(err.Error())
		os.Exit(1)
	}

	fmt.Println(*result.SubscriptionArn)
}