How to use the @aws-cdk/aws-route53-targets.LoadBalancerTarget function in @aws-cdk/aws-route53-targets

const certificateArn = StringParameter.fromStringParameterAttributes(this, 'CertArnParameter', {
      parameterName: 'CertificateArn-' + props.domainName
    }).stringValue;

    // Load balancer
    const loadBalancer = new ApplicationLoadBalancer(this, 'ServiceLB', {
      vpc,
      internetFacing: true
    });
    serviceSG.connections.allowFrom(loadBalancer, Port.tcp(80));

    const domainZone = HostedZone.fromLookup(this, 'Zone', { domainName: props.domainZone });
    new ARecord(this, "DNS", {
      zone: domainZone,
      recordName: props.domainName,
      target: AddressRecordTarget.fromAlias(new LoadBalancerTarget(loadBalancer)),
    });

    // Primary traffic listener
    const listener = loadBalancer.addListener('PublicListener', {
      port: 443,
      open: true,
      certificateArns: [certificateArn]
    });

    // Second listener for test traffic
    let testListener = loadBalancer.addListener('TestListener', {
      port: 9002, // port for testing
      protocol: ApplicationProtocol.HTTPS,
      open: true,
      certificateArns: [certificateArn]
    });

const targetProps = {
      port: 80
    };

    this.listener = this.loadBalancer.addListener('PublicListener', { port: 80 });
    this.targetGroup = this.listener.addTargets('ECS', targetProps);

    if (typeof props.domainName !== 'undefined') {
      if (typeof props.domainZone === 'undefined') {
        throw new Error('A Route53 hosted domain zone name is required to configure the specified domain name');
      }

      new ARecord(this, "DNS", {
        zone: props.domainZone,
        recordName: props.domainName,
        target: AddressRecordTarget.fromAlias(new LoadBalancerTarget(this.loadBalancer)),
      });
    }

    new cdk.CfnOutput(this, 'LoadBalancerDNS', { value: this.loadBalancer.loadBalancerDnsName });
  }

}
    }
    if (this.certificate !== undefined) {
      this.listener.addCertificateArns('Arns', [this.certificate.certificateArn]);
    }

    let domainName = this.loadBalancer.loadBalancerDnsName;
    if (typeof props.domainName !== 'undefined') {
      if (typeof props.domainZone === 'undefined') {
        throw new Error('A Route53 hosted domain zone name is required to configure the specified domain name');
      }

      const record = new ARecord(this, "DNS", {
        zone: props.domainZone,
        recordName: props.domainName,
        target: AddressRecordTarget.fromAlias(new LoadBalancerTarget(this.loadBalancer)),
      });

      domainName = record.domainName;
    }

    new cdk.CfnOutput(this, 'LoadBalancerDNS', { value: this.loadBalancer.loadBalancerDnsName });
    new cdk.CfnOutput(this, 'ServiceURL', { value: protocol.toLowerCase() + '://' + domainName });
  }