callback as Lang.Method() as Void as function parameter

Hello,

i recently started developing my first app for Garmin devices. I have an application where I want to change the interval of timers based on a state I get via REST API. So far so good.

I created my own Timer class including the Toybox.Timer and adding a getTime() Method. When I start a Timer, the time set will be stored in a privat variable I then can acces with this getter function.

This is the class:

class myTimer {
    hidden var _timer = new Timer.Timer();;
    hidden var _time;

    public function start(callback, time as Lang.Number, repeat as Lang.Boolean) as Void {
        _timer.start(callback, time , repeat);
        _time = time;
    }

    public function stop() as Void {
        _timer.stop();
    }

    public function getTime() as Lang.Number {
        return _time;
    }
}

Everything works fine. But theres one problem I encounter and find nothing about in the API docs or the Reference guide nor the sample projects. Looking at the start function:

public function start(callback, time as Lang.Number, repeat as Lang.Boolean) as Void {
    _timer.start(callback, time , repeat);
    _time = time;
}

I can tell the compiler I expect time to be a Lang.Number, and repeat a Lang.Boolean. but when I want callback to be a "callback as Lang.Method() as Void" i get a compile error. In the API docs its written exactly like this.

https://developer.garmin.com/connect-iq/api-docs/Toybox/Timer/Timer.html#start-instance_function

Error i get:

ERROR: instinct2: C:\Users\XXX\Documents\software\YYY\ZZZ\source\myTimer.mc:9,42: mismatched input '.' expecting {')', ','}
ERROR: instinct2: C:\Users\XXX\Documents\software\YYY\ZZZ\source\myTimer.mc:21: extraneous input '}' expecting {<EOF>, 'class', 'module', 'using', 'import', 'alias', 'typedef', 'public', 'const', 'native', 'var', 'enum', 'function', '('}