code: def test_dvcv011_duplicate_outputs_simple(dash_duo):
      app = Dash(__name__)
  
      @app.callback(Output("a", "children"), [Input("c", "children")])
      def c(children):
          return children
  
      @app.callback(Output("a", "children"), [Input("b", "children")])
      def c2(children):
          return children
  
      @app.callback([Output("a", "style")], [Input("c", "style")])
      def s(children):
          return (children,)
  
      @app.callback([Output("a", "style")], [Input("b", "style")])
      def s2(children):
          return (children,)
  
      app.layout = html.Div(
          [
              html.Div([], id="a"),
              html.Div(["Bye"], id="b", style={"color": "red"}),
              html.Div(["Hello"], id="c", style={"color": "green"}),
          ]
      )
  
      dash_duo.start_server(app, **debugging)
  
      specs = [
          [
              "Duplicate callback outputs",
              ["Output 0 (a.children) is already in use."],
          ],
          [
              "Duplicate callback outputs",
              ["Output 0 (a.style) is already in use."],
          ],
      ]
      check_errors(dash_duo, specs)
  
imports: import flask
  import pytest
  from dash import Dash, Input, Output, State, MATCH, ALL, ALLSMALLER, html, dcc
  from dash.testing import wait
label_desc: Use image node_id 13 for calling a global function with example usage: test_dvcv011_duplicate_outputs_simple(dash_duo) and returns: children, children, children, children