docstr: `soundfile_backend.save` can save flac format.
docstr_tok: ["`","soundfile_backend.save","`","can","save","flac","format","."]
code: def test_flac(self, sample_rate, num_channels):
      """`soundfile_backend.save` can save flac format."""
      self.assert_flac("float32", sample_rate, num_channels)
  
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 4 for calling the TestSave obj's underlying member method code with example usage: obj.test_flac(sample_rate, num_channels) without return types