"too many arguments" error

This evening I got this error :

---
Error: Too Many Arguments Error
Details: 'Failed invoking <symbol>'
Time: 2019-03-18T18:00:48Z
Part-Number: 006-B2700-00
Firmware-Version: '6.10'
Language-Code: fre
ConnectIQ-Version: 3.0.9
Filename: D825EB04
Appname: Rcherie
Stack:
- pc: 0x100023fa
File: 'C:\data\workspace\garmin\archery\source\archeryDelegate.mc'
Line: 156
Function: onHold
- pc: 0x30001d39
- pc: 0x30001f00


here is the code :
// hold to reset timer
function onHold() {
System.println("onHold");
if (Attention has :vibrate) {
var vibe = [new Attention.VibeProfile( 50, 100 )];
Attention.vibrate(vibe);
}
//TODO: resetTimer();
return true;
}


the offending line is "System.println ...." ! so I don't understand !