Callback by multi-selector is not working

Dash Python
1

Hello, I am a student studying Plotly-dash in Korea.
I wrote the new code using one example from the plotly-dash gallery.
But the app.callback of this code doesn’t work at all.
I want the pie graph updated by the multi selector.
So I wrote a number of additional functions.
All the data required for the graph were normally imported.
I really want to solve this problem…
And this is my code.

this is part of dropdown and dcc.graph

html.Div(
[
html.H6(children=‘취득자 수’,className=“subtitle padded”),
dcc.Dropdown(
id = ‘drop_down’,
options=drop_down_options,
multi=True,
value=list(DROP_DOWN.keys()),
className=“dcc_control”,
),
dcc.Graph(id=‘my-div3’)
],
className=“seven columns”,
)

this is part of app.callback

@app.callback(
Output(component_id = ‘my-div2’,component_property = ‘figure’),
[Input(component_id = ‘drop_down’, component_property = ‘value’)],
)
def update_pie(drop_down_value):

for i in range(len(drop_down_value)):
    if(drop_down_value[i] == 'age0'):
        drop_down_value[i] = '0'
    elif(drop_down_value[i] == 'age10'):
        drop_down_value[i] = '10'
    elif(drop_down_value[i] == 'age20'):
        drop_down_value[i] = '20'
    elif(drop_down_value[i] == 'age30'):
        drop_down_value[i] == '30'
    elif(drop_down_value[i] == 'age40'):
        drop_down_value[i] == '40'
    elif(drop_down_value[i] == 'age50'):
        drop_down_value[i] == '50'
    elif(drop_down_value[i] == 'age60'):
        drop_down_value[i] == '60'
    elif(drop_down_value[i] == 'age70'):
        drop_down_value[i] == '70'
    elif(drop_down_value[i] == 'age80'):
        drop_down_value[i] == '80'
    elif(drop_down_value[i] == 'age90'):
        drop_down_value[i] == '90'

dff = filter_dataframe(df, drop_down_value)

edu, life, house, medic = produce_pie_data(dff)

data = [
    go.Pie(
        labels = ['기초교육','기초생계','기초주거','기초의료'],
        values = [edu,life,house,medic],
        name = '원그래프',
        hoverinfo="text+value+percent",
        textinfo="label+percent+name",
        hole=0.5,
        marker=dict(colors=["#fac1b7", "#a9bb95", "#92d8d8"])
    )
]
layout_pie["title"] = "취득자 수"
layout_pie["font"] = dict(color="#777777")
layout_pie["legend"] = dict(
    font=dict(color="#CCCCCC", size="10"), orientation="h", bgcolor="rgba(0,0,0,0)"
)
figure = dict(data=data, layout=layout_pie)
return figure

plz help me…