Tree : Some Selection example code(options API) of document not included selecedKey data

[kimhanui]

Describe the bug

Selection example code(options API) not included selecedKey data
So, the example components cannot express 'selected' css

see the below example code of https://primevue.org/tree/#single.
This also appears at https://primevue.org/tree/#checkbox

<template>
    <ThemeSwitcher />
    <div class="card flex justify-center">
        <Toast />
        <Tree v-model:selectionKeys="selectedKey" :value="nodes" selectionMode="single" class="w-full md:w-[30rem]"></Tree>
    </div>
</template>

<script>
import { NodeService } from '@/service/NodeService';

export default {
    data() {
        return {
            nodes: null // <- HERE. NO 'selectedKey' data
        };
    },
    //ellipsis
}
</script>

Reproducer

.

PrimeVue version

4.0.6

Vue version

3.x

Language

ES6

Build / Runtime

Vue CLI App

Browser(s)

No response

Steps to reproduce the behavior

1. Go to below link
   https://primevue.org/tree/#single
   https://primevue.org/tree/#checkbox

2. And see the example code by Options API version

Expected behavior

In Options API version, selectedKey data should be included