code: def __init__(self, vispy_timer):
      BaseTimerBackend.__init__(self, vispy_timer)
      self._tk = _TkInstanceManager.get_tk_instance()
      if self._tk is None:
          raise Exception("TimerBackend: No toplevel?")
      self._id = None
      self.last_interval = 1
  
imports: from __future__ import division
  from time import sleep
  import warnings
  from ..base import BaseApplicationBackend, BaseCanvasBackend, BaseTimerBackend
  from ...util import keys
  from ...util.ptime import time
  from ...gloo import gl
label_desc: Use image node_id 1 to create a new TimerBackend object from inherited base classes: BaseTimerBackend with example: obj = TimerBackend(vispy_timer)