code: def __init__(
      self,
      src_sents,
      tgt_sents,
      src_vocab_size,
      tgt_vocab_size,
      remove_singleton=True,
  ):
      assert len(src_sents) == len(tgt_sents)
  
      print("initialize source vocabulary ..")
      self.src = VocabEntry.from_corpus(
          src_sents, src_vocab_size, remove_singleton=remove_singleton
      )
  
      print("initialize target vocabulary ..")
      self.tgt = VocabEntry.from_corpus(
          tgt_sents, tgt_vocab_size, remove_singleton=remove_singleton
      )
  
imports: import argparse
  from collections import Counter
  from itertools import chain
  import torch
  from util import read_corpus
label_desc: Use image node_id 1 to create a new Vocab object from inherited base classes: object with example: obj = Vocab(src_sents, tgt_sents, src_vocab_size, tgt_vocab_size, remove_singleton)