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

package codecommit

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

// Updates the state of a user's approval on a pull request. The user is derived
// from the signed-in account when the request is made.
func (c *Client) UpdatePullRequestApprovalState(ctx context.Context, params *UpdatePullRequestApprovalStateInput, optFns ...func(*Options)) (*UpdatePullRequestApprovalStateOutput, error) {
	if params == nil {
		params = &UpdatePullRequestApprovalStateInput{}
	}

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

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

type UpdatePullRequestApprovalStateInput struct {

	// The approval state to associate with the user on the pull request.
	//
	// This member is required.
	ApprovalState types.ApprovalState

	// The system-generated ID of the pull request.
	//
	// This member is required.
	PullRequestId *string

	// The system-generated ID of the revision.
	//
	// This member is required.
	RevisionId *string

	noSmithyDocumentSerde
}

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

	noSmithyDocumentSerde
}

func (c *Client) addOperationUpdatePullRequestApprovalStateMiddlewares(stack *middleware.Stack, options Options) (err error) {
	if err := stack.Serialize.Add(&setOperationInputMiddleware{}, middleware.After); err != nil {
		return err
	}
	err = stack.Serialize.Add(&awsAwsjson11_serializeOpUpdatePullRequestApprovalState{}, middleware.After)
	if err != nil {
		return err
	}
	err = stack.Deserialize.Add(&awsAwsjson11_deserializeOpUpdatePullRequestApprovalState{}, middleware.After)
	if err != nil {
		return err
	}
	if err := addProtocolFinalizerMiddlewares(stack,
    
func (c *Client) addOperationUpdatePullRequestApprovalStateMiddlewares(stack *middleware.Stack, options Options) (err error) {
	if err := stack.Serialize.Add(&setOperationInputMiddleware{}, middleware.After); err != nil {
		return err
	}
	err = stack.Serialize.Add(&awsAwsjson11_serializeOpUpdatePullRequestApprovalState{}, middleware.After)
	if err != nil {
		return err
	}
	err = stack.Deserialize.Add(&awsAwsjson11_deserializeOpUpdatePullRequestApprovalState{}, middleware.After)
	if err != nil {
		return err
	}
	if err := addProtocolFinalizerMiddlewares(stack, options, "UpdatePullRequestApprovalState"); 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 = addOpUpdatePullRequestApprovalStateValidationMiddleware(stack); err != nil {
		return err
	}
	if err = stack.Initialize.Add(newServiceMetadataMiddleware_opUpdatePullRequestApprovalState(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
}