code: def get_mask_token(self):
      return self.MASK_TOKEN
  
file_path: nlpaug/nlpaug/model/lang_models/bert.py
imports: import logging
  from nlpaug.model.lang_models import LanguageModels
  from nlpaug.util.selection.filtering import *
label_desc: Use image node_id 9 for calling the Bert obj's underlying member method code with example usage: obj.get_mask_token() and returns: self