SWIFT - Observe contentSize fro the tableView

ViewController.Swift

class ViewController: UIViewController {
    @IBOutlet weak var tableView: UITableView!
    @IBOutlet weak var heightTableView: NSLayoutConstraint!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.addObserver(self, forKeyPath: "contentSize", options: .new, context: nil)
    }
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        tableView.removeObserver(self, forKeyPath: "contentSize")
    }
    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        if let obj = object as? UITableView {
            if obj == self.tableView && keyPath == "contentSize" {
                 heightTableView.constant = tableView.contentSize.height
            }
        }
    }
}