code: def test_AddBackgroundNoise(self):
      random_generator = np.random.default_rng(1)
      self.evaluate_class(
          audaugs.AddBackgroundNoise(
              background_audio=None,
              snr_level_db=10.0,
              seed=random_generator,
          ),
          fname="add_background_noise2",
      )
  
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 2 for calling the TransformsAudioUnitTest obj's underlying member method code with example usage: obj.test_AddBackgroundNoise() without return types