如何在Dash中创建404错误页面(绘图)？

import dash
import dash_core_components as dcc
import dash_html_components as html
import plotly.graph_objs as go

app = dash.Dash(__name__)

app.layout = html.Div([
    html.H1('404 - Page Not Found'),
    html.Div('Sorry, the page you are looking for does not exist.'),
    dcc.Graph(
        figure={
            'data': [go.Scatter(
                x=[0, 1, 2],
                y=[0, 1, 2],
                mode='markers',
                marker={'size': 15}
            )],
            'layout': go.Layout(
                title='404 Error',
                xaxis={'title': 'X-axis'},
                yaxis={'title': 'Y-axis'}
            )
        }
    )
])

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