Dequeue cell for reuse

//存两个字典， 一个是identifier - cell
//一个是 identifier - cell type
var dic = [String: UITableViewCell.Type]() // identifier : cell
dic["cell"] = UITableViewCell.self
var cells = [String : [UITableViewCell]]()
cells["cell"] = [UITableViewCell]()

extension UITableView{
    func dequeueMyReusableCell(with Identifier: String) -> UITableViewCell{
        if let list = cells[Identifier], list.count > 0 {
            var l = list
            let cell = l.removeFirst()
            cell.prepareForReuse()
            cells[Identifier] = l
            return cell
        }else{
            if let type = dic[Identifier] {
                return type.init()
            }else{
                return UITableViewCell()
            }
        }
    }
}

var tableView = UITableView()
let cell = tableView.dequeueMyReusableCell(with: "cell")