code: def _vispy_start(self, interval):
      raise NotImplementedError()
  
imports: from __future__ import division
  from ..base import BaseApplicationBackend, BaseCanvasBackend, BaseTimerBackend
  from ...util import keys
  from ...None import config
label_desc: Use image node_id 2 for calling the TimerBackend obj's underlying member method code with example usage: obj._vispy_start(interval) without return types