code: def test_cbva003_list_single_output(dash_duo):
      app = Dash(__name__)
      app.layout = html.Div(
          [
              html.Div("Hi", id="in"),
              html.Div(id="out1"),
              html.Div(id="out2"),
          ]
      )
  
      @app.callback(Output("out1", "children"), Input("in", "children"))
      def o1(i):
          return "1: " + i
  
      @app.callback(
          [Output("out2", "children")], [Input("in", "children")]
      )
      def o2(i):
          return ("2: " + i,)
  
      dash_duo.start_server(app)
      dash_duo.wait_for_text_to_equal("#out1", "1: Hi")
      dash_duo.wait_for_text_to_equal("#out2", "2: Hi")
  
file_path: dash/tests/integration/callbacks/test_validation.py
imports: import pytest
  from dash import Dash, Input, Output, State, html
  from dash.exceptions import InvalidCallbackReturnValue, IncorrectTypeException
label_desc: Use image node_id 3 for calling a global function with example usage: test_cbva003_list_single_output(dash_duo) and returns: unknown, unknown