class_docstr: Class that holds a vocabulary for the dataset.
class_docstr_tok: ["Class","that","holds","a","vocabulary","for","the","dataset","."]
code: def bos(self):
      return self._bos
  
imports: import random
  import numpy
  from textattack.shared.utils import LazyLoader
label_desc: Use image node_id 2 for calling the Vocabulary obj's underlying member method code with example usage: obj.bos() and returns: self