用户如何将自己的值添加到dash_core_components.Dropdown？

import dash_core_components as dcc

app = dash.Dash(__name__)

app.layout = html.Div([
    dcc.Dropdown(
        id='my-dropdown',
        options=[
            {'label': 'Value 1', 'value': 'value1'},
            {'label': 'Value 2', 'value': 'value2'},
            {'label': 'Value 3', 'value': 'value3'}
        ],
        value='value1'
    ),
    html.Div(id='output')
])

@app.callback(
    Output('output', 'children'),
    [Input('my-dropdown', 'value')]
)
def update_output(value):
    return f'You have selected {value}'

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