How to create a python dashboard with dash?

i want to use pythons dash library to create an html dashboard. Unfortunatly it always raises the following error code when i try to call the html:

enter image description here

the full traceback:

enter image description here

The Code i'm using is:

app.Layout = html.Div([
    
    html.H1('Example Dashboard - BeeStuff', style={'text align': 'center'}),
    
    dcc.Dropdown(id='slct_year',
                options=[
                    {'labels': '2015', 'value': 2015},
                    {'labels': '2016', 'value': 2016},
                    {'labels': '2017', 'value': 2017},
                    {'labels': '2018', 'value': 2018}],
                multi=False,
                value=2015,
                style={'width':'40%'}
                ),
    
    html.Div(id='output_container', children=[]),
    html.Br(),
    
    dcc.Graph(id='my_bee_map', figure={})
    
])

Hope that someone could help me. PS: i already updated the library