问AttributeError:当我尝试使用app.layout=dbc.Container()构造破折号应用程序的布局时，'tuple‘对象没有属性' layout’

EN

import dash
import pandas as pd
import numpy as np
import database
from dash import Dash, dcc, html
import dash_bootstrap_components as dbc

# create a dash app which is compatible with mobile devices
app = dash.Dash(__name__, external_stylesheets=[dbc.themes.BOOTSTRAP],
                meta_tags=[{'name': 'viewport',
                'content': 'width=device-width, initial-scale=1.0'}]
                ),
# structure the layout of the web app
app.layout =dbc.Container(
    html.H1(children='Hello Dash'))

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