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How to add callback function to multiselect dropdown menu

I am creating multiselect dropdown menu callback function

the problem is in state the value shows for the last country selected.

image

like the picture last thing in country is india so only its states are showing

my code for dropdown menus is

     id="control-card",
    children=[
        html.P("Select Country"),
        dcc.Dropdown(
            id="country-select",
            options=[{"label": k, "value": k} for k in all_option.keys()],
            value=['All'],
            multi=True,

        ),


        html.Br(),
        html.P("Select State"),
        dcc.Dropdown(
            id="State-select",
            options=[{"label": i, "value": i} for i in all_option_state.keys()],
            value=['All'],
            multi=True
        ),

my code for callback function is:
@app.callback(
dash.dependencies.Output(‘State-select’, ‘options’),
[dash.dependencies.Input(‘country-select’, ‘value’)])

   def update_state_src(selected_country):
    if 'All' in selected_country:

       for k in selected_country:
           result= [{'label': i, 'value': i} for i in all_option_state[k]]
           return result
    if not selected_country:
          a=[]
          return a

     if 'All' not in selected_country:
          if selected_country:
          for j in selected_country:
              a= [{'label': i, 'value': i} for i in all_option_state[j]]
              return a