code: def on_draw(self, event):
      clear(color=True, depth=True)
      self.program_e.draw("lines", self.index)
      self.program.draw("points")
  
file_path: vispy/examples/demo/gloo/graph.py
imports: import numpy
  from vispy import gloo, app
  from vispy.gloo import set_viewport, set_state, clear
label_desc: Use image node_id 3 for calling the Canvas obj's underlying member method code with example usage: obj.on_draw(event) without return types