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: api_op_AddTags.go
    path of file: ./repos/aws-sdk-go-v2/service/opensearch
    
    the code of the file until where you have to start completion: // Code generated by smithy-go-codegen DO NOT EDIT.

package opensearch

import (
	"context"
	"fmt"
	awsmiddleware "github.com/aws/aws-sdk-go-v2/aws/middleware"
	"github.com/aws/aws-sdk-go-v2/service/opensearch/types"
	"github.com/aws/smithy-go/middleware"
	smithyhttp "github.com/aws/smithy-go/transport/http"
)

// Attaches tags to an existing Amazon OpenSearch Service domain. Tags are a set
// of case-sensitive key-value pairs. A domain can have up to 10 tags. For more
// information, see Tagging Amazon OpenSearch Service domains (https://docs.aws.amazon.com/opensearch-service/latest/developerguide/managedomains-awsresourcetagging.html)
// .
func (c *Client) AddTags(ctx context.Context, params *AddTagsInput, optFns ...func(*Options)) (*AddTagsOutput, error) {
	if params == nil {
		params = &AddTagsInput{}
	}

	result, metadata, err := c.invokeOperation(ctx, "AddTags", params, optFns, c.addOperationAddTagsMiddlewares)
	if err != nil {
		return nil, err
	}

	out := result.(*AddTagsOutput)
	out.ResultMetadata = metadata
	return out, nil
}

// Container for the parameters to the AddTags operation. Specifies the tags to
// attach to the domain.
type AddTagsInput struct {

	// Amazon Resource Name (ARN) for the OpenSearch Service domain to which you want
	// to attach resource tags.
	//
	// This member is required.
	ARN *string

	// List of resource tags.
	//
	// This member is required.
	TagList []types.Tag

	noSmithyDocumentSerde
}

type AddTagsOutput struct {
	// Metadata pertaining to the operation's result.
	ResultMetadata middleware.Metadata

	noSmithyDocumentSerde
}

func (c *Client) addOperationAddTagsMiddlewares(stack *middleware.Stack, options Options) (err error) {
	if err := stack.Serialize.Add(&setOperationInputMiddleware{}, middleware.After); err != nil {
		return err
	}
	err = stack
    
func (c *Client) addOperationAddTagsMiddlewares(stack *middleware.Stack, options Options) (err error) {
	if err := stack.Serialize.Add(&setOperationInputMiddleware{}, middleware.After); err != nil {
		return err
	}
	err = stack.Serialize.Add(&awsRestjson1_serializeOpAddTags{}, middleware.After)
	if err != nil {
		return err
	}
	err = stack.Deserialize.Add(&awsRestjson1_deserializeOpAddTags{}, middleware.After)
	if err != nil {
		return err
	}
	if err := addProtocolFinalizerMiddlewares(stack, options, "AddTags"); err != nil {
		return fmt.Errorf("add protocol finalizers: %v", err)
	}

	if err = addlegacyEndpointContextSetter(stack, options); err != nil {
		return err
	}
	if err = addSetLoggerMiddleware(stack, options); err != nil {
		return err
	}
	if err = addClientRequestID(stack); err != nil {
		return err
	}
	if err = addComputeContentLength(stack); err != nil {
		return err
	}
	if err = addResolveEndpointMiddleware(stack, options); err != nil {
		return err
	}
	if err = addComputePayloadSHA256(stack); err != nil {
		return err
	}
	if err = addRetry(stack, options); err != nil {
		return err
	}
	if err = addRawResponseToMetadata(stack); err != nil {
		return err
	}
	if err = addRecordResponseTiming(stack); err != nil {
		return err
	}
	if err = addClientUserAgent(stack, options); err != nil {
		return err
	}
	if err = smithyhttp.AddErrorCloseResponseBodyMiddleware(stack); err != nil {
		return err
	}
	if err = smithyhttp.AddCloseResponseBodyMiddleware(stack); err != nil {
		return err
	}
	if err = addSetLegacyContextSigningOptionsMiddleware(stack); err != nil {
		return err
	}
	if err = addOpAddTagsValidationMiddleware(stack); err != nil {
		return err
	}
	if err = stack.Initialize.Add(newServiceMetadataMiddleware_opAddTags(options.Region), middleware.Before); err != nil {
		return err
	}
	if err = addRecursionDetection(stack); err != nil {
		return err
	}
	if err = addRequestIDRetrieverMiddleware(stack); err != nil {
		return err
	}
	if err = addResponseErrorMiddleware(stack); err != nil {
		return err
	}
	if err = addRequestResponseLogging(stack, options); err != nil {
		return err
	}
	if err = addDisableHTTPSMiddleware(stack, options); err != nil {
		return err
	}
	return nil
}