code: def test_path_continuously_varying_line_width_op_update(self):
      xs = [1, 2, 3, 4]
      ys = xs[::-1]
      path = HoloMap(
          {
              0: Path(
                  [{"x": xs, "y": ys, "line_width": [1, 7, 3, 2]}],
                  vdims="line_width",
              ),
              1: Path(
                  [{"x": xs, "y": ys, "line_width": [3, 8, 2, 3]}],
                  vdims="line_width",
              ),
          }
      ).opts(linewidth="line_width")
      plot = mpl_renderer.get_plot(path)
      artist = plot.handles["artist"]
      self.assertEqual(artist.get_linewidths(), [1, 7, 3, 2])
      plot.update((1,))
      self.assertEqual(artist.get_linewidths(), [3, 8, 2, 3])
  
imports: import numpy
  import pytest
  from holoviews.core import NdOverlay
  from holoviews.core.options import AbbreviatedException
  from holoviews.core.spaces import HoloMap
  from holoviews.element import Contours, Path, Polygons
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 4 for calling the TestPathPlot obj's underlying member method code with example usage: obj.test_path_continuously_varying_line_width_op_update() without return types