code: def __repr__(self):
      return "Vocab(source %d words, target %d words)" % (
          len(self.src),
          len(self.tgt),
      )
  
imports: import argparse
  from collections import Counter
  from itertools import chain
  import torch
  from util import read_corpus
label_desc: Use image node_id 2 for calling the Vocab obj's underlying member method code with example usage: obj.__repr__() and returns: unknown