code: def on_draw(self, event):
      gloo.clear(color=(0.0, 0.0, 0.0, 1.0))
      self.program.draw("line_strip")
  
file_path: vispy/examples/demo/gloo/signals.py
imports: from vispy import gloo
  from vispy import app
  import numpy
  import math
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