code: def test_output_util_backend_kwargs(self):
      self.assertEqual(
          OutputSettings.options.get("backend", None), None
      )
      output(backend="bokeh")
      self.assertEqual(
          OutputSettings.options.get("backend", None), "bokeh"
      )
  
imports: from unittest import SkipTest
  from pyviz_comms import CommManager
  from holoviews import Store, notebook_extension
  from holoviews.core.options import OptionTree
  from holoviews.element.comparison import ComparisonTestCase
  from holoviews.plotting import bokeh, mpl
  from holoviews.util import Options, OutputSettings, opts, output
  from ..utils import LoggingComparisonTestCase
label_desc: Use image node_id 6 for calling the TestOutputUtil obj's underlying member method code with example usage: obj.test_output_util_backend_kwargs() without return types