docstr: Returns
  -------
  str
      The name of the backend.
code: def _vispy_get_backend_name(self):
      """
      Returns
      -------
      str
          The name of the backend.
      """
      return tk.__name__
  
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 for calling the ApplicationBackend obj's underlying member method code with example usage: obj._vispy_get_backend_name() and returns: tk