code: def nat_normalize_text(text):
      text = unicodedata.normalize("NFKC", text)
      text = text.lower().strip()
      sil = FLAGS.special_phonemes[FLAGS.sil_index]
      text = re.sub(r"[\n.,:]+", f" {sil} ", text)
      text = text.replace('"', " ")
      text = re.sub(r"\s+", " ", text)
      text = re.sub(r"[.,:;?!]+", f" {sil} ", text)
      text = re.sub("[ ]+", " ", text)
      text = re.sub(f"( {sil}+)+ ", f" {sil} ", text)
      return text.strip()
  
file_path: underthesea/underthesea/pipeline/say/viettts_/synthesizer.py
imports: import re
  import unicodedata
  from argparse import ArgumentParser
  from pathlib import Path
  import soundfile
  from .hifigan.mel2wave import mel2wave
  from .nat.config import FLAGS
  from .nat.text2mel import text2mel
label_desc: Use image node_id 1 for calling a global function with example usage: nat_normalize_text(text) and returns: text