code: def on_draw(self, event):
      gl.glClear(gl.GL_COLOR_BUFFER_BIT)
      gl.glDrawArrays(gl.GL_TRIANGLE_STRIP, 0, 4)
  
file_path: vispy/examples/gloo/gl/quad.py
imports: import numpy
  from vispy import app
  from vispy.gloo import gl
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