class_docstr: A mapping from indices to vocab elements.
class_docstr_tok: ["A","mapping","from","indices","to","vocab","elements","."]
code: def __getitem__(self, item):
      return self._vocab[item]
  
imports: import itertools
  from collections import Counter
  from typing import Dict, List, Optional, Tuple
  import torch
  from pytext.common.constants import SpecialTokens, Token
  from pytext.utils import cuda, precision
label_desc: Use image node_id 10 for calling the Vocabulary obj's underlying member method code with example usage: obj.__getitem__(item) and returns: self