def requestNodeAddedUpdate(self,caller,event):
    if not self.pendingUpdate:
      qt.QTimer.singleShot(0, self.wrappedNodeAddedUpdate)
      self.pendingUpdate = True
Start a SingleShot timer that will check the fiducials
dataset/ETHPy150Open acil-bwh/SlicerCIP/Scripted/InteractiveLobeSegmentation/InteractiveLobeSegmentation.py/ILSVisualizationWidget.requestNodeAddedUpdate