code: def setUpClass(cls):
      super().setUpClass()
      with open(AUDIO_METADATA_PATH, "r") as f:
          cls.metadata = json.load(f)
  
imports: import json
  import random
  import unittest
  import numpy
  from augly import audio
  from augly.tests.audio_tests.base_unit_test import BaseAudioUnitTest
  from augly.utils import AUDIO_METADATA_PATH
label_desc: Use image node_id 1 for calling the TransformsAudioUnitTest obj's underlying member method code with example usage: obj.setUpClass(cls) without return types