code: def test_trimesh_op_node_color(self):
      edges = [(0, 1, 2), (1, 2, 3)]
      nodes = [
          (-1, -1, 0, "red"),
          (0, 0, 1, "green"),
          (0, 1, 2, "blue"),
          (1, 0, 3, "black"),
      ]
      trimesh = TriMesh((edges, Nodes(nodes, vdims="color"))).opts(
          node_color="color"
      )
      plot = bokeh_renderer.get_plot(trimesh)
      cds = plot.handles["scatter_1_source"]
      glyph = plot.handles["scatter_1_glyph"]
      self.assertEqual(
          property_to_dict(glyph.fill_color), {"field": "node_color"}
      )
      self.assertEqual(glyph.line_color, "black")
      self.assertEqual(
          cds.data["node_color"],
          np.array(["red", "green", "blue", "black"]),
      )
  
imports: import numpy
  from bokeh.models import EdgesAndLinkedNodes, NodesAndLinkedEdges, NodesOnly, Patches
  from bokeh.models.mappers import CategoricalColorMapper, LinearColorMapper
  from holoviews.core.data import Dataset
  from holoviews.element import Chord, Graph, Nodes, TriMesh, VLine, circular_layout
  from holoviews.plotting.bokeh.util import property_to_dict
  from holoviews.util.transform import dim
  from .test_plot import TestBokehPlot, bokeh_renderer
label_desc: Use image node_id 6 for calling the TestBokehTriMeshPlot obj's underlying member method code with example usage: obj.test_trimesh_op_node_color() without return types