code: def _vispy_set_visible(self, visible):
      if not visible:
          raise NotImplementedError("Cannot hide the RFB widget")
  
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 12 for calling the CanvasBackend obj's underlying member method code with example usage: obj._vispy_set_visible(visible) without return types