code: def on_draw(self, event):
      gloo.clear("black")
  
      for visual in self.lines:
          visual.draw()
  
file_path: vispy/examples/basics/visuals/arrows.py
imports: import sys
  import numpy
  from vispy import app, gloo, visuals
  from vispy.geometry import curves
  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