code: def _vispy_get_physical_size(self):
      return self._physical_size
  
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 17 for calling the CanvasBackend obj's underlying member method code with example usage: obj._vispy_get_physical_size() and returns: self