How to use the @aws-cdk/aws-elasticloadbalancingv2.TargetType function in @aws-cdk/aws-elasticloadbalancingv2

private attach(_targetGroup: elbv2.ITargetGroup): elbv2.LoadBalancerTargetProps {
    return {
      targetType: elbv2.TargetType.INSTANCE,
      targetJson: { id: this.instanceId, port: this.port }
    };
  }
}

private attach(_targetGroup: elbv2.ITargetGroup): elbv2.LoadBalancerTargetProps {
    return {
      targetType: elbv2.TargetType.LAMBDA,
      targetJson: { id: this.fn.functionArn }
    };
  }
}

private attach(_targetGroup: elbv2.ITargetGroup): elbv2.LoadBalancerTargetProps {
    return {
      targetType: elbv2.TargetType.IP,
      targetJson: { id: this.ipAddress, port: this.port, availabilityZone: this.availabilityZone }
    };
  }
}

public attachToNetworkTargetGroup(targetGroup: elbv2.INetworkTargetGroup): elbv2.LoadBalancerTargetProps {
    this.targetGroupArns.push(targetGroup.targetGroupArn);
    return { targetType: elbv2.TargetType.INSTANCE };
  }