code: def _vispy_update(self):
      self.request_draw()
  
imports: import asyncio
  from ..base import BaseApplicationBackend, BaseCanvasBackend, BaseTimerBackend
  from ...app import Timer
  from ...util import keys
  from ._offscreen_util import OffscreenContext, FrameBufferHelper
label_desc: Use image node_id 14 for calling the CanvasBackend obj's underlying member method code with example usage: obj._vispy_update() without return types