docstr: Also save a vocab name to class name mapping in state dict. 
docstr_tok: ["Also","save","a","vocab","name","to","class","name","mapping","in","state","dict","."]
code: def state_dict(self):
      """Also save a vocab name to class name mapping in state dict."""
      state = OrderedDict()
      key2class = OrderedDict()
      for k, v in self._vocabs.items():
          state[k] = v.state_dict()
          key2class[k] = type(v).__name__
      state["_key2class"] = key2class
      return state
  
file_path: stanza/stanza/models/ner/vocab.py
imports: from collections import Counter, OrderedDict
  from stanza.models.common.vocab import BaseVocab, BaseMultiVocab, CharVocab, CompositeVocab
  from stanza.models.common.vocab import VOCAB_PREFIX
  from stanza.models.common.pretrain import PretrainedWordVocab
  from stanza.models.pos.vocab import WordVocab
label_desc: Use image node_id 1 for calling the MultiVocab obj's underlying member method code with example usage: obj.state_dict() and returns: state