code: def to_serializable(self):
      contents = super(CBOWVocabulary, self).to_serializable()
      contents.update({"mask_token": self._mask_token})
      return contents
  
imports: from typing import Dict
label_desc: Use image node_id 2 for calling the CBOWVocabulary obj's underlying member method code with example usage: obj.to_serializable() and returns: contents