如何在python Dash中访问应用布局中的输入值？

import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output

app = dash.Dash(__name__)

app.layout = html.Div([
    dcc.Input(id='input', value='', type='text'),
    html.Div(id='output')
])

@app.callback(
    Output('output', 'children'),
    [Input('input', 'value')]
)
def update_output(value):
    return f'输入的值是：{value}'

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

import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output

app = dash.Dash(__name__)

app.layout = html.Div([
    dcc.Input(id='input', value='', type='text'),
    html.Div(id='output')
])

@app.callback(
    Output('output', 'children'),
    [Input('input', 'value')]
)
def update_output(value):
    return f'输入的值是：{value}'

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