code: def applyVertexColor(renderer, brdf, channel_names):
      if "COLOR_0" in channel_names:
          vertexColor_idx = channel_names.index("COLOR_0")
          vertexColor_uvwGen = renderer.classes.UVWGenChannel()
          vertexColor_uvwGen.uvw_channel = vertexColor_idx
  
          vertexColor_tex = renderer.classes.TexUVW()
          vertexColor_tex.uvwgen = vertexColor_uvwGen
  
          diffuseVertexColor_tex = renderer.classes.TexAColorOp()
          diffuseVertexColor_tex.color_a = brdf.diffuse
          diffuseVertexColor_tex.color_b = vertexColor_tex
  
          brdf.diffuse = diffuseVertexColor_tex.product
  
imports: from __future__ import print_function
  import os
  import sys
  import json
  import vray
  from .None import parserUtils
  from .None import cameraUtils
  import numpy
  from tempfile import mkstemp
  import math
  import pyquaternion
  import base64
  from ..None import testUtils
label_desc: Use image node_id 4 for calling a global function with example usage: applyVertexColor(renderer, brdf, channel_names) without return types