code: def test_cbpi004_positional_arg(dash_duo):
      app = Dash(__name__)
      app.layout = html.Div(
          [html.Button("click", id="btn"), html.Div(id="out")]
      )
  
      @app.callback(
          Output("out", "children"), Input("btn", "n_clicks"), True
      )
      def f(n):
          return n
  
      dash_duo.start_server(app)
      dash_duo._wait_for_callbacks()
  
      dash_duo.wait_for_text_to_equal("#out", "")
  
      dash_duo.find_element("#btn").click()
  
      dash_duo.wait_for_text_to_equal("#out", "1")
  
file_path: dash/tests/integration/callbacks/test_prevent_initial.py
imports: import json
  import pytest
  from flaky import flaky
  from dash import Dash, Input, Output, MATCH, html
  from dash.exceptions import PreventUpdate
label_desc: Use image node_id 8 for calling a global function with example usage: test_cbpi004_positional_arg(dash_duo) and returns: n