code: def _change_backend(backend):
      if backend not in image_utils.get_available_backends():
          pytest.skip("{} is not installed".format(backend))
  
      # change backend arbitrary
      image_utils.set_backend(backend)
      assert image_utils.get_backend() == backend
  
file_path: nnabla/python/test/utils/test_image_utils.py
imports: from __future__ import division
  import pytest
  import numpy
  from nnabla.utils import image_utils
  from nnabla.logger import logger
  from nnabla.testing import assert_allclose
label_desc: Use image node_id 1 for calling a global function with example usage: _change_backend(backend) without return types