TableViewで複数選択したものを全て取得する方法

エラーはなし

import UIKit

class SupportForm03ViewController: UIViewController , UITableViewDelegate, UITableViewDataSource {
    @IBOutlet var OS: UITableView!
    @IBOutlet var NextPage: UIButton!

    var rowListArray = [Int]()
    var itemListArray = [Int]()
    var sortArray = [Int]()

    var NameSend = ""
    var EmailSend = ""
    var ProductSend = ""
    var OSSend = ""
    var ContentsSend = ""
    var SolutionSend = ""


    var ALLOS = ["macOS 11.2.2","macOS 11.2.1", "macOS 11.2", "macOS 11.1", "macOS 11.0.1", "macOS 11.0.1","macOS 10.15.7","macOS 10.15.6","macOS 10.15.6","macOS 10.15.6","macOS 10.15.5","macOS 10.15.5","macOS 10.15.4","macOS 10.15.4","macOS 10.15.3","macOS 10.15.2","macOS 10.15.1","macOS 10.15.0","macOS 10.15.0","macOS 10.15.0",
                 "iPadOS14.4","iPadOS14.3","iPadOS14.2.1","iPadOS14.2","iPadOS14.1","iPadOS14.0.1","iPadOS14","iPadOS13.7","iPadOS13.6.1","iPadOS13.6","iPadOS13.5.1","iPadOS13.5","iPadOS13.4.1","iPadOS13.4","iPadOS13.3.1","iPadOS13.3","iPadOS13.2.3","iPadOS13.2.2","iPadOS13.2","iPadOS13.1.3","iPadOS13.1.2","iPadOS13.1.1","iPadOS13.1",
                 "iOS14.4","iOS14.3","iOS14.2.1","iOS14.2","iOS14.1","iOS14.0.1","iOS14","iOS13.7","iOS13.6.1","iOS13.6","iOS13.5.1","iOS13.5","iOS13.4.1","iOS13.4","iOS13.3.1","iOS13.3","iOS13.2.3","iOS13.2.2","iOS13.2","iOS13.1.3","iOS13.1.2","iOS13.1.1","iOS13.1","iOS13",
                 "watchOS7.3.1","watchOS7.3","watchOS7.2","watchOS7.1","watchOS7.0.3","watchOS7.0.2","watchOS7.0.1","watchOS7","watchOS6.2.8","watchOS6.2.6","watchOS6.2.5","watchOS6.2.1","watchOS6.2","watchOS6.1.3","watchOS6.1.2","watchOS6.1.1","watchOS6.1","watchOS6.0.1","watchOS6",
                 "3.3.1","3.5.1","3.7.2","6.3.2","6.7.8","6.8.8","1A661","1A673","1A691","2A364","2B584","2B488","2C54","2D15","2D27","3A283",
                 "その他(不具合内容の欄で入力お願いします。)"]


    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return ALLOS.count
    }

   func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
        let cell = UITableViewCell()
        cell.backgroundColor = UIColor.clear
        //  セルの選択時の背景色を消す
        cell.selectionStyle = UITableViewCell.SelectionStyle.none
        cell.textLabel?.text = ALLOS[indexPath.row]
        //  セルの選択状況の判定
        if (rowListArray.contains(indexPath.row)){
            cell.accessoryType = .checkmark
        }else{
            cell.accessoryType = .none
        }
        return cell
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath){
        let cell = tableView.cellForRow(at: indexPath)
        //  選択したセルにチェックマークが無い場合
        if(cell?.accessoryType == UITableViewCell.AccessoryType.none){
            cell?.accessoryType = .checkmark
            self.rowListArray.append(indexPath.row)
        }else{
        //  選択したセルにチェックマークがある場合
            cell?.accessoryType = .none
            let  listNumber = rowListArray.filter ({ (n:Int) -> Bool in
                if n != indexPath.row{
                    return true
                }else{
                    return false
                }})
            rowListArray = listNumber
        }
        //  配列を昇順で並び替え、
        //  都道府県コードに変換する。
        sortArray = rowListArray.sorted{$0 < $1}
        itemListArray = sortArray.map{$0 + 1}
        print("OS\(itemListArray)")
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        OS.allowsMultipleSelection = true

        // Do any additional setup after loading the view.
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        let vc = segue.destination as! SupportForm04ViewController
            vc.NameSend = NameSend
            vc.EmailSend = EmailSend
            vc.ProductSend = ProductSend
        if let row = OS.indexPathForSelectedRow?.row {
            vc.OSSend = ALLOS[row]
        }
    }

    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destination.
        // Pass the selected object to the new view controller.
    }
    */

}