code: def on_draw(self, ev):
      gloo.clear("black", depth=True)
      for line in self.lines:
          line.draw()
  
file_path: vispy/examples/basics/visuals/line_transform.py
imports: import numpy
  from vispy import app, gloo, visuals
  from vispy.visuals.transforms import STTransform, LogTransform, MatrixTransform, PolarTransform
label_desc: Use image node_id 2 for calling the Canvas obj's underlying member method code with example usage: obj.on_draw(ev) without return types