code: def convert_fraction(written: str):
      """
      converts fraction to standard form, e.g "½" -> "1/2", "1 ½" -> "1 1/2"
  
      Args:
          written: written form
      Returns:
          written: modified form
      """
      written = re.sub(" ½", " 1/2", written)
      written = re.sub(" ⅓", " 1/3", written)
      written = re.sub(" ⅔", " 2/3", written)
      written = re.sub(" ¼", " 1/4", written)
      written = re.sub(" ¾", " 3/4", written)
      written = re.sub(" ⅕", " 1/5", written)
      written = re.sub(" ⅖", " 2/5", written)
      written = re.sub(" ⅗", " 3/5", written)
      written = re.sub(" ⅘", " 4/5", written)
      written = re.sub(" ⅙", " 1/6", written)
      written = re.sub(" ⅚", " 5/6", written)
      written = re.sub(" ⅛", " 1/8", written)
      written = re.sub(" ⅜", " 3/8", written)
      written = re.sub(" ⅝", " 5/8", written)
      written = re.sub(" ⅞", " 7/8", written)
      written = re.sub("^½", "1/2", written)
      written = re.sub("^⅓", "1/3", written)
      written = re.sub("^⅔", "2/3", written)
      written = re.sub("^¼", "1/4", written)
      written = re.sub("^¾", "3/4", written)
      written = re.sub("^⅕", "1/5", written)
      written = re.sub("^⅖", "2/5", written)
      written = re.sub("^⅗", "3/5", written)
      written = re.sub("^⅘", "4/5", written)
      written = re.sub("^⅙", "1/6", written)
      written = re.sub("^⅚", "5/6", written)
      written = re.sub("^⅛", "1/8", written)
      written = re.sub("^⅜", "3/8", written)
      written = re.sub("^⅝", "5/8", written)
      written = re.sub("^⅞", "7/8", written)
      written = re.sub("-½", "-1/2", written)
      written = re.sub("-⅓", "-1/3", written)
      written = re.sub("-⅔", "-2/3", written)
      written = re.sub("-¼", "-1/4", written)
      written = re.sub("-¾", "-3/4", written)
      written = re.sub("-⅕", "-1/5", written)
      written = re.sub("-⅖", "-2/5", written)
      written = re.sub("-⅗", "-3/5", written)
      written = re.sub("-⅘", "-4/5", written)
      written = re.sub("-⅙", "-1/6", written)
      written = re.sub("-⅚", "-5/6", written)
      written = re.sub("-⅛", "-1/8", written)
      written = re.sub("-⅜", "-3/8", written)
      written = re.sub("-⅝", "-5/8", written)
      written = re.sub("-⅞", "-7/8", written)
      written = re.sub("([0-9])\s?½", "\\1 1/2", written)
      written = re.sub("([0-9])\s?⅓", "\\1 1/3", written)
      written = re.sub("([0-9])\s?⅔", "\\1 2/3", written)
      written = re.sub("([0-9])\s?¼", "\\1 1/4", written)
      written = re.sub("([0-9])\s?¾", "\\1 3/4", written)
      written = re.sub("([0-9])\s?⅕", "\\1 1/5", written)
      written = re.sub("([0-9])\s?⅖", "\\1 2/5", written)
      written = re.sub("([0-9])\s?⅗", "\\1 3/5", written)
      written = re.sub("([0-9])\s?⅘", "\\1 4/5", written)
      written = re.sub("([0-9])\s?⅙", "\\1 1/6", written)
      written = re.sub("([0-9])\s?⅚", "\\1 5/6", written)
      written = re.sub("([0-9])\s?⅛", "\\1 1/8", written)
      written = re.sub("([0-9])\s?⅜", "\\1 3/8", written)
      written = re.sub("([0-9])\s?⅝", "\\1 5/8", written)
      written = re.sub("([0-9])\s?⅞", "\\1 7/8", written)
      return written
  
file_path: NeMo/nemo/collections/nlp/data/text_normalization/utils.py
imports: import string
  from copy import deepcopy
  import regex
  from tqdm import tqdm
  from nemo.collections.nlp.data.text_normalization import constants
label_desc: Use image node_id 4 for calling a global function with example usage: convert_fraction(written) and returns: written