code: def test_audio_utils_backend_manager():
      with pytest.raises(ValueError):
          audio_utils.set_backend("not_installed_module")
  
file_path: nnabla/python/test/utils/test_audio_utils.py
imports: from __future__ import division
  import pytest
  import numpy
  from six import BytesIO, StringIO
  from nnabla.logger import logger
  from nnabla.testing import assert_allclose
label_desc: Use image node_id 2 for calling a global function with example usage: test_audio_utils_backend_manager() without return types