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: iam_add_member.go
    path of file: ./repos/golang-samples/kms
    
    the code of the file until where you have to start completion: // Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writin
    
func iamAddMember(w io.Writer, name, member string) error {
	// NOTE: The resource name can be either a key or a key ring. If IAM
	// permissions are granted on the key ring, the permissions apply to all keys
	// in the key ring.
	//
	// name := "projects/my-project/locations/us-east1/keyRings/my-key-ring/cryptoKeys/my-key"
	// member := "user:foo@example.com"

	// Create the client.
	ctx := context.Background()
	client, err := kms.NewKeyManagementClient(ctx)
	if err != nil {
		return fmt.Errorf("failed to create kms client: %w", err)
	}
	defer client.Close()

	// Get the current IAM policy.
	handle := client.ResourceIAM(name)
	policy, err := handle.Policy(ctx)
	if err != nil {
		return fmt.Errorf("failed to get IAM policy: %w", err)
	}

	// Grant the member permissions. This example grants permission to use the key
	// to encrypt data.
	policy.Add(member, "roles/cloudkms.cryptoKeyEncrypterDecrypter")
	if err := handle.SetPolicy(ctx, policy); err != nil {
		return fmt.Errorf("failed to save policy: %w", err)
	}

	fmt.Fprintf(w, "Updated IAM policy for %s\n", name)
	return nil
}