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

package billingconductor

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

// Creates a custom line item that can be used to create a one-time fixed charge
// that can be applied to a single billing group for the current or previous
// billing period. The one-time fixed charge is either a fee or discount.
func (c *Client) CreateCustomLineItem(ctx context.Context, params *CreateCustomLineItemInput, optFns ...func(*Options)) (*CreateCustomLineItemOutput, error) {
	if params == nil {
		params = &CreateCustomLineItemInput{}
	}

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

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

type CreateCustomLineItemInput struct {

	// The Amazon Resource Name (ARN) that references the billing group where the
	// custom line item applies to.
	//
	// This member is required.
	BillingGroupArn *string

	// A CustomLineItemChargeDetails that describes the charge details for a custom
	// line item.
	//
	// This member is required.
	ChargeDetails *types.CustomLineItemChargeDetails

	// The description of the custom line item. This is shown on the Bills page in
	// association with the charge value.
	//
	// This member is required.
	Description *string

	// The name of the custom line item.
	//
	// This member is required.
	Name *string

	// The Amazon Web Services account in which this custom line item will be applied
	// to.
	AccountId *string

	// A time range for which the custom line item is effective.
	BillingPeriodRange *types.CustomLineItemBillingPeriodRange

	// The token that is needed to support idempotency. Idempotency isn't currently
	// supported, but will be implemented in a future update.
	ClientToken *string

	// A map that contains tag keys and tag values that are attached to a custom line
	// item.
	Tags map[string]string

	noSmithyDocumentSerde
}

type CreateCustomLineItemOutput struct {

	// The Amazon Resource Name
    
func (c *Client) addOperationCreateCustomLineItemMiddlewares(stack *middleware.Stack, options Options) (err error) {
	if err := stack.Serialize.Add(&setOperationInputMiddleware{}, middleware.After); err != nil {
		return err
	}
	err = stack.Serialize.Add(&awsRestjson1_serializeOpCreateCustomLineItem{}, middleware.After)
	if err != nil {
		return err
	}
	err = stack.Deserialize.Add(&awsRestjson1_deserializeOpCreateCustomLineItem{}, middleware.After)
	if err != nil {
		return err
	}
	if err := addProtocolFinalizerMiddlewares(stack, options, "CreateCustomLineItem"); 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 = addIdempotencyToken_opCreateCustomLineItemMiddleware(stack, options); err != nil {
		return err
	}
	if err = addOpCreateCustomLineItemValidationMiddleware(stack); err != nil {
		return err
	}
	if err = stack.Initialize.Add(newServiceMetadataMiddleware_opCreateCustomLineItem(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
}