code: def __len__(self) -> int:
      return self.total_sentence_count
  
imports: import logging
  from abc import abstractmethod
  from pathlib import Path
  from typing import Generic, List, Optional, Union
  import torch.utils.data.dataloader
  from deprecated.sphinx import deprecated
  from flair.data import DT, FlairDataset, Sentence, Tokenizer
  from flair.tokenization import SegtokTokenizer, SpaceTokenizer
label_desc: Use image node_id 4 for calling the MongoDataset obj's underlying member method code with example usage: obj.__len__() and returns: self