code: def test_contours_empty_path(self):
      contours = Contours(
          [
              pd.DataFrame(
                  [], columns=["x", "y", "color", "line_width"]
              ),
              pd.DataFrame(
                  {
                      "x": np.random.rand(10),
                      "y": np.random.rand(10),
                      "color": ["red"] * 10,
                      "line_width": [3] * 10,
                  },
                  columns=["x", "y", "color", "line_width"],
              ),
          ],
          vdims=["color", "line_width"],
      ).opts(color="color", line_width="line_width")
      plot = bokeh_renderer.get_plot(contours)
      glyph = plot.handles["glyph"]
      self.assertEqual(glyph.line_color, "red")
      self.assertEqual(glyph.line_width, 3)
  
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 4 for calling the TestContoursPlot obj's underlying member method code with example usage: obj.test_contours_empty_path() without return types