How to use the serializr.date function in serializr

import {Difficulty} from './Difficulty';
import {v4 as uuid} from 'uuid';

export type ProfileId = string;

const nullEstateEvent = new EstateEvent();
nullEstateEvent.shown = true;

export class Profile {
  @serializable(identifier()) id: ProfileId = uuid();
  @serializable difficulty: Difficulty;
  @serializable @observable isNameFinalized: boolean = false;
  @serializable @observable name: string = '';
  @serializable(object(Path)) @observable path: Path;
  @serializable @observable week: number = 0;
  @serializable(date()) @observable dateOfLastSave: Date = new Date();
  @serializable @observable selectedQuestId?: QuestId;
  @serializable @observable gold: number = 0;
  @observable debt: number = 0;

  @computed get goldAfterDebt () { return this.gold - this.debt; }

  @serializable(object(EstateEvent))
  @observable
  estateEvent = nullEstateEvent;

  @serializable(list(object(Hero)))
  @observable
  coach: Hero[] = [];

  @serializable(list(object(Hero)))
  @observable