如何使用Dash upload组件显示包含我上传的文件的pandas数据帧？

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

app = dash.Dash(__name__)

app.layout = html.Div([
    dcc.Upload(
        id='upload-data',
        children=html.Div([
            '拖放或 ',
            html.A('选择文件')
        ]),
        style={
            'width': '50%',
            'height': '60px',
            'lineHeight': '60px',
            'borderWidth': '1px',
            'borderStyle': 'dashed',
            'borderRadius': '5px',
            'textAlign': 'center',
            'margin': '10px'
        },
        multiple=False
    ),
    html.Div(id='output-data')
])

@app.callback(Output('output-data', 'children'),
              [Input('upload-data', 'contents'),
               Input('upload-data', 'filename')])
def update_output(contents, filename):
    if contents is not None:
        content_type, content_string = contents.split(',')

        decoded = base64.b64decode(content_string)
        try:
            if 'csv' in filename:
                # 读取上传的CSV文件
                df = pd.read_csv(io.StringIO(decoded.decode('utf-8')))
            elif 'xls' in filename:
                # 读取上传的Excel文件
                df = pd.read_excel(io.BytesIO(decoded))
        except Exception as e:
            return html.Div([
                '发生错误：',
                html.Pre(str(e))
            ])

        # 显示数据帧
        return html.Div([
            html.H5(filename),
            html.Table(
                [html.Tr([html.Th(col) for col in df.columns])] +
                [html.Tr([
                    html.Td(df.iloc[i][col]) for col in df.columns
                ]) for i in range(min(len(df), 5))]
            )
        ])

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