     ///   - position: Point in time in beats
     ///
     public func addTempoEventAt(tempo bpm: Double, position: AKDuration) {
-        if isAVSequencer { return }
+        if isAVSequencer {
+            print("AVSequencer ERROR ! addTempoEventAt only work if not isAVSequencer ")
+            return }
 
         let constrainedTempo = min(max(bpm, 10.0), 280.0)
 

            if isAVSequencer {
                return Double(avSequencer.rate)
            } else {
                return nil
            }
        }
        set {
            if isAVSequencer {
                avSequencer.rate = Float(newValue!)
            }
        }
    }

    ///   - duration: Length of time after the start position to clear
    ///
    public func clearRange(start start: AKDuration, duration: AKDuration) {
        if isAVSequencer {
            print("AVSequencer ERROR ! clearRange only work if not isAVSequencer ")
        return }

        for track in tracks {
            track.clearRange(start: start, duration: duration)
