code: def on_draw(self, event):
      self.context.clear(color="white")
      self.markers.draw()
  
file_path: vispy/examples/basics/visuals/markers.py
imports: import numpy
  from vispy import app, visuals
  from vispy.visuals.transforms import STTransform
label_desc: Use image node_id 2 for calling the Canvas obj's underlying member method code with example usage: obj.on_draw(event) without return types