code: def normalize_unit(self, unit):
      unit = super().normalize_unit(unit)
      if unit:
          unit = unit.replace(" ", "\xa0")
      return unit
  
imports: import csv
  import os
  import re
  import lzma
  import logging
  import numpy
  import torch
  from .vocab import BaseVocab, VOCAB_PREFIX, UNK_ID
  from stanza.models.common.utils import open_read_binary, open_read_text
  from stanza.resources.common import DEFAULT_MODEL_DIR
label_desc: Use image node_id 2 for calling the PretrainedWordVocab obj's underlying member method code with example usage: obj.normalize_unit(unit) and returns: unit