code: def test_polygons_colored(self):
      polygons = NdOverlay(
          {
              j: Polygons(
                  [[(i**j, i, j) for i in range(10)]], vdims="Value"
              )
              for j in range(5)
          }
      )
      plot = bokeh_renderer.get_plot(polygons)
      for i, splot in enumerate(plot.subplots.values()):
          cmapper = splot.handles["color_mapper"]
          self.assertEqual(cmapper.low, 0)
          self.assertEqual(cmapper.high, 4)
          source = splot.handles["source"]
          self.assertEqual(source.data["Value"], np.array([i]))
  
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 2 for calling the TestPolygonPlot obj's underlying member method code with example usage: obj.test_polygons_colored() without return types