code: def size(self):
      return len(self.vocab)
  
file_path: DIG/dig/ggraph/method/JTVAE/fast_jtnn/vocab.py
imports: import rdkit
  import rdkit.Chem
  import copy
label_desc: Use image node_id 5 for calling the Vocab obj's underlying member method code with example usage: obj.size() and returns: len