code: def available_backends():
      
  
      # Standard-library WAV and AIFF readers.
      from . import rawread
      result = [rawread.RawAudioFile]
  
      # Core Audio.
      if _ca_available():
          from . import macca
          result.append(macca.ExtAudioFile)
  
      # GStreamer.
      if _gst_available():
          from . import gstdec
          result.append(gstdec.GstAudioFile)
  
      # MAD.
      if _mad_available():
          from . import maddec
          result.append(maddec.MadAudioFile)
  
      # FFmpeg.
      if ffdec.available():
          result.append(ffdec.FFmpegAudioFile)
  
      return result
docs: Returns a list of backends that are available on this system.