Generic parameter 'Self' could not be inferred in RxDataSources

Question

I am trying RxDataSources https://github.com/RxSwiftCommunity/RxDataSources for simple TableView

class ViewController: UIViewController {

    @IBOutlet weak var tableView: UITableView!
    let disposeBag = DisposeBag()

    override func viewDidLoad() {
        super.viewDidLoad()

        let items = [
            CustomItem(id: 12, title: "name"),
            CustomItem(id: 22, title: "your age"),
            CustomItem(id: 77, title: "style")
        ]

        let data = Observable<[CustomItem]>.just(items)

        data.bind(to: tableView.rx.items(cellIdentifier: "CustomCell", cellType: CustomCell)) {
            index, model, cell in
            cell.questionLbl.text = model
            }
            .disposed(by: disposeBag)
    }

}

class CustomCell: UITableViewCell {
    @IBOutlet weak var questionLbl: UILabel!
}

struct CustomItem: Equatable {
    let id: Int
    let title: String

    static func == (lhs: CustomItem, rhs: CustomItem) -> Bool {
        return lhs.id == rhs.id
    }
}

And I got this error:

Generic parameter 'Self' could not be inferred

p.s. as you see - I added Equatable to my struct but it also not working. same time if I change array of custom object to array of Strings, everything starts to work fine.