code: def unit2id(self, unit):
      if len(self.ignore) > 0 and unit in self.ignore:
          return self._unit2id[EMPTY]
      else:
          return super().unit2id(unit)
  
file_path: stanza/stanza/models/pos/vocab.py
imports: from collections import Counter, OrderedDict
  from stanza.models.common.vocab import BaseVocab, BaseMultiVocab, CharVocab
  from stanza.models.common.vocab import CompositeVocab, VOCAB_PREFIX, EMPTY, EMPTY_ID
label_desc: Use image node_id 3 for calling the WordVocab obj's underlying member method code with example usage: obj.unit2id(unit) and returns: self, super