code: def get_available_backends(self):
      return [
          key
          for key, value in self.backends.items()
          if value is not None
      ]
  
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 5 for calling the AudioUtilsBackendManager obj's underlying member method code with example usage: obj.get_available_backends() and returns: unknown