docstr: `soundfile_backend.save` can save wav with more than 2 channels.
docstr_tok: ["`","soundfile_backend.save","`","can","save","wav","with","more","than","2","channels","."]
code: def test_multiple_channels(self, dtype, num_channels):
      """`soundfile_backend.save` can save wav with more than 2 channels."""
      sample_rate = 8000
      self.assert_wav(dtype, sample_rate, num_channels, num_frames=None)
  
imports: import io
  from unittest.mock import patch
  from torchaudio._internal import module_utils
  from torchaudio.backend import soundfile_backend
  from torchaudio_unittest.common_utils import get_wav_data, load_wav, nested_params, PytorchTestCase, skipIfNoModule, TempDirMixin
  from .common import fetch_wav_subtype, parameterize, skipIfFormatNotSupported
label_desc: Use image node_id 2 for calling the TestSave obj's underlying member method code with example usage: obj.test_multiple_channels(dtype, num_channels) without return types