如何在Dash中创建选项卡和子选项卡？

import dash
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash(__name__)

app.layout = html.Div([
    dcc.Tabs(id='tabs', value='tab-1', children=[
        dcc.Tab(label='选项卡1', value='tab-1', children=[
            html.Div([
                html.H3('这是选项卡1的内容')
            ])
        ]),
        dcc.Tab(label='选项卡2', value='tab-2', children=[
            html.Div([
                html.H3('这是选项卡2的内容')
            ])
        ]),
        dcc.Tab(label='选项卡3', value='tab-3', children=[
            html.Div([
                html.H3('这是选项卡3的内容')
            ])
        ]),
    ]),
    html.Div(id='tab-content')
])

@app.callback(Output('tab-content', 'children'),
              [Input('tabs', 'value')])
def render_content(tab):
    if tab == 'tab-1':
        return html.Div([
            html.H3('选项卡1的内容')
        ])
    elif tab == 'tab-2':
        return html.Div([
            html.H3('选项卡2的内容')
        ])
    elif tab == 'tab-3':
        return html.Div([
            html.H3('选项卡3的内容')
        ])

if __name__ == '__main__':
    app.run_server(debug=True)