code: def __len__(self):
      return len(self.data)
  
imports: import random
  import numpy
  import os
  from collections import Counter
  import logging
  import torch
  import stanza.models.common.seq2seq_constant
  from stanza.models.common.data import map_to_ids, get_long_tensor, get_float_tensor, sort_all
  from stanza.models.lemma.vocab import Vocab, MultiVocab
  from stanza.models.lemma import edit
  from stanza.models.common.doc import *
label_desc: Use image node_id 4 for calling the DataLoader obj's underlying member method code with example usage: obj.__len__() and returns: len