code: def fetch_wav_subtype(dtype, encoding, bits_per_sample):
      subtype = {
          (None, None): dtype2subtype(dtype),
          (None, 8): "PCM_U8",
          ("PCM_U", None): "PCM_U8",
          ("PCM_U", 8): "PCM_U8",
          ("PCM_S", None): "PCM_32",
          ("PCM_S", 16): "PCM_16",
          ("PCM_S", 32): "PCM_32",
          ("PCM_F", None): "FLOAT",
          ("PCM_F", 32): "FLOAT",
          ("PCM_F", 64): "DOUBLE",
          ("ULAW", None): "ULAW",
          ("ULAW", 8): "ULAW",
          ("ALAW", None): "ALAW",
          ("ALAW", 8): "ALAW",
      }.get((encoding, bits_per_sample))
      if subtype:
          return subtype
      raise ValueError(
          f"wav does not support ({encoding}, {bits_per_sample})."
      )
  
file_path: audio/test/torchaudio_unittest/backend/dispatcher/soundfile/common.py
imports: import itertools
  from unittest import skipIf
  from parameterized import parameterized
  from torchaudio._internal.module_utils import is_module_available
label_desc: Use image node_id 5 for calling a global function with example usage: fetch_wav_subtype(dtype, encoding, bits_per_sample) and returns: subtype