renaming original functions

functions.dart

  void _choose() async {
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () async {
          _choose();
        },
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }