code: def test_add_background_noise_intensity(self):
      intensity = audaugs.add_background_noise_intensity(
          metadata={}, snr_level_db=10.0
      )
      self.assertAlmostEqual(intensity, 90.90909091)
  
imports: import unittest
  import numpy
  from augly import audio
label_desc: Use image node_id 1 for calling the IntensityAudioUnitTest obj's underlying member method code with example usage: obj.test_add_background_noise_intensity() without return types