Should add to dispose bag

ViewController.swift

class ViewController : UIViewController {
  let viewModel = ViewModel()
  
  private let disposeBag = DisposeBag()
  
  override func viewDidLoad(){
    super.viewDidLoad()

    self.viewModel.navigationVariable.asObservable()
      .subscribeNext { data in

        let newViewModel = NewViewModel(data)
        let newViewController = NewViewController()
        newViewController.viewModel = newViewModel

        self.navigationController?.pushViewController(newViewController, animated:false)
    }.addDisposableTo(disposeBag)
  }
}