code: def build_vocab(self):
      self._id2unit = VOCAB_PREFIX + self.data
      self._unit2id = {w: i for i, w in enumerate(self._id2unit)}
  
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 1 for calling the PretrainedWordVocab obj's underlying member method code with example usage: obj.build_vocab() without return types