code: def sliderHandler(self, event):
      value = event.GetInt() / 1000.0
      self.param.set(value)
  
imports: import wx
  import numpy
  from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg
  from matplotlib.figure import Figure
label_desc: Use image node_id 2 for calling the SliderGroup obj's underlying member method code with example usage: obj.sliderHandler(event) without return types