code: def test_bars_multi_level_two_factors_in_overlay(self):
      # See: https://github.com/holoviz/holoviews/pull/5850
      box = Bars(
          (["1", "2", "3"] * 10, ["A", "B"] * 15, np.random.randn(30)),
          ["Group", "Category"],
          "Value",
      ).aggregate(function=np.mean)
      overlay = Overlay([box])
      plot = bokeh_renderer.get_plot(overlay)
      left_axis = plot.handles["plot"].left[0]
      assert isinstance(left_axis, LinearAxis)
  
imports: import numpy
  from bokeh.models import CategoricalColorMapper, LinearAxis, LinearColorMapper
  from holoviews.core.overlay import NdOverlay, Overlay
  from holoviews.element import Bars
  from holoviews.plotting.bokeh.util import property_to_dict
  from ..utils import ParamLogStream
  from .test_plot import TestBokehPlot, bokeh_renderer
label_desc: Use image node_id 8 for calling the TestBarPlot obj's underlying member method code with example usage: obj.test_bars_multi_level_two_factors_in_overlay() without return types