Как мне сохранить структуру данных в Realm?

Хочу сохранить структуру данных в реалм и отображать эти данные из реалма в tableView

class ViewController: UIViewController {
    
    class Record : Comparable {
        let calendar: Calendar = {
        var calendar = Calendar.autoupdatingCurrent
        calendar.locale = Locale(identifier: "ru_RU")
            return calendar
        }()
            
        var date: Date
        init(date: Date) {
            self.date = date
        }
        
        static func == (lhs: Record, rhs: Record) -> Bool {
            lhs.date == rhs.date
        }
        static func < (lhs: Record, rhs: Record) -> Bool {
            lhs.date < rhs.date
        }
    }
        
    class Section : Record {
            
        private let formatter: DateFormatter = {
            let formatter = DateFormatter()
            formatter.dateFormat = "yyyy/MM"
            formatter.locale = Locale(identifier: "ru_RU")
            return formatter
        }()
            
        var title: String {
            formatter.string(from: date)
        }
        var items = [SectionItem]()
            
        func addRecord(_ record: SectionItem) {
            items.append(record)
        }
    }
        
    class SectionItem : Record {
            
        private let formatter: DateFormatter = {
            let formatter = DateFormatter()
            formatter.dateFormat = "yyyy/MM/dd HH:mm"
            formatter.locale = Locale(identifier: "ru_RU")
            return formatter
        }()
            
        var year: Int {
            calendar.component(.year, from: date)
        }
        var month: Int {
            calendar.component(.month, from: date)
        }
        var title: String {
            formatter.string(from: date)
        }
    }
    
    @IBOutlet weak var tableView: UITableView!
    @IBOutlet weak var datePicker: UIDatePicker!
    @IBOutlet weak var createButton: UIButton!
    
    var items = [SectionItem]()
    var sections = [Section]()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.delegate = self
        tableView.dataSource = self
        self.tableView.register(UINib(nibName: "TableViewCell", bundle: nil), forCellReuseIdentifier: "TableViewCell")
    }
    
    func sortData() {

        if items.isEmpty {
            return
        }
        
        items.sort()
        sections = []

        var year = 0
        var month = 0
        var section: Section!
            
        for item in items {
            if section == nil || item.year != year || item.month != month {
                section = Section(date: item.date)
                sections.append(section)
            }
            section.addRecord(item)
            year = item.year
            month = item.month
            }
        }
    
    @IBAction func createButtonAction(_ sender: Any) {
        let dateRecord = SectionItem(date: datePicker.date)
        items.append(dateRecord)
        sortData()
        tableView.reloadData()
    }
    
}

extension ViewController: UITableViewDelegate, UITableViewDataSource {
    func numberOfSections(in tableView: UITableView) -> Int {
        return sections.count
    }
    
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return sections[section].title
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return sections[section].items.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell") as! TableViewCell
        cell.labelCell?.text = sections[indexPath.section].items[indexPath.row].title
        return cell
    }