code: def test_extractLabelNames(self):
      labelsDict = self.jsonParser.extractLabels(
          self.json_with_multiple_versions
      )
      labelNames = self.jsonParser.extractLabelNames(labelsDict)
      self.assertListEqual(
          labelNames,
          ["final", "version_1", "version_2", "version_3", "version_4"],
      )
  
imports: import json
  import os
  import sys
  import unittest
  from MONAILabelReviewerLib.ImageData import ImageData
  from MONAILabelReviewerLib.JsonParser import JsonParser
label_desc: Use image node_id 19 for calling the JsonParserTest obj's underlying member method code with example usage: obj.test_extractLabelNames() without return types