MainViewController.swift

class MainViewController: UIViewController {

    @IBOutlet var bottomErrorContainer: UIView!
    @IBOutlet var bottomErrorLabel: UILabel!
    
    func viewDidLoad() {
        // ...
        
        viewModel.minorError
            .bind(onNext: { [unowned self] error in
                switch error {
                case .some(let error):
                    self.bottomErrorContainer.isHidden = false
                    self.bottomErrorLabel.text = error
                case .none:
                    self.bottomErrorContainer.isHidden = true
                }
            })
            .disposed(by: disposeBag)
    }
}