content: from dash import Dash, Input, Output, dcc, State, html, callback
  
  from tests.background_callback.utils import get_background_callback_manager
  
  background_callback_manager = get_background_callback_manager()
  handle = background_callback_manager.handle
  
  app = Dash(__name__, background_callback_manager=background_callback_manager)
  
  app.layout = html.Div(
      [
          html.Div(id="output"),
          html.Button("click", id="click"),
          dcc.Store(data="stored", id="stored"),
      ]
  )
  
  
  @callback(
      Output("output", "children"),
      State("stored", "data"),
      Input("click", "n_clicks"),
      background=True,
      prevent_initial_call=True,
  )
  def update_output(stored, n_clicks):
      return stored
  
  
  if __name__ == "__main__":
      app.run(debug=True)
  