code: def set_audio_backend(backend: Optional[str]):  # noqa
      """Set the global backend.
  
      This is a no-op when dispatcher mode is enabled.
  
      Args:
          backend (str or None): Name of the backend.
              One of ``"sox_io"`` or ``"soundfile"`` based on availability
              of the system. If ``None`` is provided the  current backend is unassigned.
      """
      pass
  
imports: from typing import List, Optional
  from torchaudio._internal.module_utils import deprecated
  from .None import utils
  from .common import AudioMetaData
label_desc: Use image node_id 3 for calling a global function with example usage: set_audio_backend(backend) without return types