code: def test_contours_line_width_op(self):
      contours = Contours(
          [
              {("x", "y"): [(0, 0), (0, 1), (1, 0)], "line_width": 7},
              {("x", "y"): [(1, 0), (1, 1), (0, 1)], "line_width": 3},
          ],
          vdims="line_width",
      ).opts(line_width="line_width")
      plot = bokeh_renderer.get_plot(contours)
      cds = plot.handles["source"]
      glyph = plot.handles["glyph"]
      self.assertEqual(
          property_to_dict(glyph.line_width), {"field": "line_width"}
      )
      self.assertEqual(cds.data["line_width"], np.array([7, 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 8 for calling the TestContoursPlot obj's underlying member method code with example usage: obj.test_contours_line_width_op() without return types