Dropdown menu in folium doesn't work (Python code)

I try to create a choropleth with Folium. The choropleth should show the different growth rates of the countries (lower growth rate = dark green, growth rate > 0 = red). In addition, I would like to have a dropdown menu where I can choose between the different years. The default year should be 2016 (or any other, doesn't matter). The dataframe is called final_consumption data (columns = COUNTRY, YEAR, PRODUCT, VALUE, GROWTH_RATE). The colors are still not correct set up, I know. But may main problem is that the dropdown menu doesn't appear and the year is not considered.

Here is the code:

import folium
import ipywidgets as widgets
from IPython.display import HTML, display
import geopandas as gpd

final_consumption_data = data_completed_coordinates[data_completed_coordinates['PRODUCT'] == 'Final      
consumption']

world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))
world.to_file("world_countries.geojson", driver='GeoJSON')
geojson_path = "world_countries.geojson"

map_choropleth = folium.Map(tiles='OpenStreetMap', location=[48, 8], zoom_start=2)

choropleth = folium.Choropleth(
    geo_data=geojson_path,
    name='choropleth',
    data=final_consumption_data,
    columns=['COUNTRY', 'GROWTH_RATE'],
    key_on='feature.properties.name',
    fill_color='RdYlGn',
    fill_opacity=0.7,
    line_opacity=0.2,
    legend_name='Consumption growth rate (%)',
    highlight=True
).add_to(map_choropleth)

folium.LayerControl().add_to(map_choropleth)

year_dropdown = widgets.Dropdown(options=final_consumption_data['YEAR'].unique(),
                                 value=2016,
                                 description='Year',
                                 disabled=False,
                                 )


def update_choropleth(year):
    # print(f"Selected year: {year}")
    filtered_data = final_consumption_data[final_consumption_data['YEAR'] == year]
    # print(filtered_data.head())
    choropleth.geojson.data = filtered_data
    choropleth.options['name'] = f'Consumption growth rate (%) for year {year}'



year_dropdown.observe(lambda change: update_choropleth(change.new), names='value')

display(year_dropdown)
display(map_choropleth)

map_choropleth.save('choropleth_interactive.html') 

As you can see, I tried some debugging by printing out some steps. The data frame is fine. But the variable year_dropdown and the function update_choropleth seems to have bugs (even if I tried different ways to program it as you might see).