How to use the mobx-keystone.types.model function in mobx-keystone

@modelAction
  setDone(done: boolean) {
    this.done = done
  }

  @modelAction
  setText(text: string) {
    this.text = text
  }
}

@model("todoSample/TodoList")
export class TodoList extends Model({
  // in this case the default uses an arrow function to create the object since it is not a primitive
  // and we need a different array for each model instane
  todos: tProp(types.array(types.model(Todo)), () => []),

  // if we didn't require runtime type checking
  // todos: prop(() => [])
}) {
  // standard mobx decorators (such as computed) can be used as usual, since props are observables
  @computed
  get pending() {
    return this.todos.filter(t => !t.done)
  }

  @computed
  get done() {
    return this.todos.filter(t => t.done)
  }

  @modelAction