addOnWrongStrokeCallback method Null safety

void addOnWrongStrokeCallback(
  1. Function? onWrongStrokeCallback
)

Implementation

void addOnWrongStrokeCallback(Function? onWrongStrokeCallback) {
  if (onWrongStrokeCallback != null) {
    _onWrongStrokeCallbacks.add(onWrongStrokeCallback);
  }
}