code: def _import_backend(self, backend):
      try:
          module = importlib.import_module(
              "nnabla.utils.audio_utils.{}_utils".format(backend)
          )
      except ImportError:
          # log backend status in _check_backend
          module = None
  
      self.backends[backend] = module
  
file_path: nnabla/python/src/nnabla/utils/audio_utils/backend_manager.py
imports: import importlib
  from collections import OrderedDict
label_desc: Use image node_id 3 for calling the AudioUtilsBackendManager obj's underlying member method code with example usage: obj._import_backend(backend) without return types