code: def test_empty_polygons_plot(self):
      poly = Polygons([], vdims=["Intensity"])
      plot = bokeh_renderer.get_plot(poly)
      source = plot.handles["source"]
      self.assertEqual(len(source.data["xs"]), 0)
      self.assertEqual(len(source.data["ys"]), 0)
      self.assertEqual(len(source.data["Intensity"]), 0)
  
imports: import datetime
  import numpy
  import pandas
  from bokeh.models import CategoricalColorMapper, LinearColorMapper
  from holoviews.core import HoloMap, NdOverlay
  from holoviews.core.options import Cycle
  from holoviews.element import Contours, Path, Polygons
  from holoviews.plotting.bokeh.util import property_to_dict
  from holoviews.streams import PolyDraw
  from holoviews.util.transform import dim
  from .test_plot import TestBokehPlot, bokeh_renderer
label_desc: Use image node_id 5 for calling the TestPolygonPlot obj's underlying member method code with example usage: obj.test_empty_polygons_plot() without return types