code: def __init__(self, delimiter=" "):
      super().__init__(delimiter)
      self.use_mask = True
  
imports: from typing import Dict, List, Optional, Set
  import numpy
  from pytext.common.constants import SpecialTokens, Token
  from pytext.config.component import Component, ComponentType
  from pytext.config.pytext_config import ConfigBase
  from pytext.data.data_structures.annotation import Annotation, Intent, Root, Slot
  from pytext.data.utils import VocabBuilder, Vocabulary
label_desc: Use image node_id 1 to create a new MaskedVocabBuilder object from inherited base classes: VocabBuilder with example: obj = MaskedVocabBuilder(delimiter)