code: def get_symbol_list(
      symbol_list: str = "english_characters",
      cmudict_root: Optional[str] = "./",
  ) -> List[str]:
      if symbol_list == "english_characters":
          return (
              [_pad]
              + list(_special)
              + list(_punctuation)
              + list(_letters)
          )
      elif symbol_list == "english_phonemes":
          return (
              [_pad]
              + list(_special)
              + list(_punctuation)
              + CMUDict(cmudict_root).symbols
          )
      else:
          raise ValueError(
              f"The `symbol_list` {symbol_list} is not supported."
              f"Supported `symbol_list` includes {available_symbol_set}."
          )
  
file_path: audio/examples/pipeline_tacotron2/text/text_preprocessing.py
imports: import re
  from typing import List, Optional, Union
  from torchaudio.datasets import CMUDict
  from unidecode import unidecode
  from .numbers import normalize_numbers
label_desc: Use image node_id 1 for calling a global function with example usage: get_symbol_list(symbol_list, cmudict_root) and returns: unknown, unknown