class_docstr: This is the training version of the dataset.
class_docstr_tok: ["This","is","the","training","version","of","the","dataset","."]
code: def init_sent_ids(self):
      self.sentence_ids = []
      self.cumlen = [0]
      for i, para in enumerate(self.sentences):
          for j in range(len(para)):
              self.sentence_ids += [(i, j)]
              self.cumlen += [
                  self.cumlen[-1] + len(self.sentences[i][j][0])
              ]
  
imports: from bisect import bisect_right
  from copy import copy
  import numpy
  import random
  import logging
  import re
  import torch
  from torch.utils.data import Dataset
  from .vocab import Vocab
  from stanza.models.common.utils import sort_with_indices, unsort
label_desc: Use image node_id 4 for calling the DataLoader obj's underlying member method code with example usage: obj.init_sent_ids() without return types