flutterでscoped modelで作成されたclassの中のメソッドをコールしたい

b.dart内のonPressedの処理内でa.dart内Deviceクラスのtestメソッドを実行したいのですが、
どうすればよいのかわかりません。
DeviceクラスはBlueModelクラス内で宣言されています。

a.dart

dart
1class Device extends BluetoothDevice {
2
3  Device({this.connection, @required this.id, this.name})
4      : super(id: id, name: name);
5
6  void test(){
7  }
8}
9
10class BlueModel extends Model {
11  FlutterBlue _blue = FlutterBlue.instance;
12  Map<DeviceIdentifier, Device> _devices = {};
13  Device currentDevice;
14  TabController tabController;
15
16  BlueModel({@required this.tabController}) : assert(tabController != null);
17
18  bool _loading = false;
19
20  Map<DeviceIdentifier, Device> get devices => _devices;
21
22  static BlueModel of(BuildContext context) =>
23      ScopedModel.of<BlueModel>(context);
24
25  bool get loading => _loading;
26
27  Future<void> scan() async {
28    _loading = true;
29    notifyListeners();
30
31    var scannedResult = Map<DeviceIdentifier, Device>();
32
33    await for (ScanResult result in _blue.scan(timeout: Duration(seconds: 2))) {
34      var dev = result.device;
35      if (dev.name.contains('ZEAL')) {
36        scannedResult[dev.id] = Device(id: dev.id, name: dev.name);
37      }
38    }
39
40    _devices.forEach((id, dev) {
41      if (scannedResult[id] == null && !_devices[id].connected)
42        _devices.remove(id);
43    });
44
45    scannedResult.forEach((id, dev) {
46      if (_devices[id] == null) _devices[id] = dev;
47    });
48
49    _loading = false;
50    notifyListeners();
51  }
52
53  void connect(Device d) async {
54    d.currentState = BluetoothDeviceState.connecting;
55    notifyListeners();
56    var deviceState = await d.state;
57    print('Device State: $deviceState');
58    if (_devices[d.id].connection == null &&
59        deviceState != BluetoothDeviceState.connected) {
60      _devices[d.id].connection = _blue.connect(d).listen((s) {
61        print('Current State: ${d.currentState}');
62        if (s == BluetoothDeviceState.connected) {
63          d.initiate(notifyListeners);
64        }
65      });
66    } else {
67      d.currentState = BluetoothDeviceState.connecting;
68      notifyListeners();
69      await Future.delayed(Duration(milliseconds: 500));
70      d.currentState = BluetoothDeviceState.disconnected;
71      notifyListeners();
72    }
73  }
74
75  void disconect(Device d) {
76    d.dispose();
77    if (d.id == currentDevice.id) currentDevice = null;
78    notifyListeners();
79  }
80
81  void select(Device d) async {
82    print('Checking...');
83
84    if (!d.connected) return;
85
86    if (currentDevice != null && d.id != currentDevice.id) {
87      print('Stop current device');
88      currentDevice.stopReadWeight();
89      currentDevice.stopListen();
90    }
91
92    print('Checked!!!');
93
94    if (!d.listening) {
95      print('Start listening');
96      currentDevice = d;
97      currentDevice.startListen(notifyListeners);
98      currentDevice.startReadWeight();
99    }
100
101    tabController.animateTo(1);
102  }
103}

b.dart

dart
1class BasicFunctions extends StatelessWidget {
2  @override
3  Widget build(BuildContext context) {
4    return Wrap(
5            alignment: WrapAlignment.spaceAround,
6            runSpacing: 20.0,           
7            children: <Widget>[
8              ControlButton(
9                text: 'aaa',
10                onPressed: () {
11                  //このonPressedの中でDeviceクラスのtestメソッドを実行したい
12                },
13              ),
14            ],
15          );
16  }
17}