code: def test_save_gsm(self):
      self.assert_save_consistency("gsm", num_channels=1)
      with self.assertRaises(
          RuntimeError,
          msg="gsm format only supports single channel audio.",
      ):
          self.assert_save_consistency("gsm", num_channels=2)
      with self.assertRaises(
          RuntimeError,
          msg="gsm format only supports a sampling rate of 8kHz.",
      ):
          self.assert_save_consistency("gsm", sample_rate=16000)
  
imports: import os
  import torch
  from parameterized import parameterized
  from torchaudio.backend import sox_io_backend
  from torchaudio_unittest.common_utils import get_wav_data, load_wav, nested_params, PytorchTestCase, save_wav, skipIfNoExec, skipIfNoSox, skipIfNoSoxEncoder, sox_utils, TempDirMixin, TorchaudioTestCase
  from .common import get_enc_params, name_func
label_desc: Use image node_id 9 for calling the SaveTest obj's underlying member method code with example usage: obj.test_save_gsm() without return types