code: def __len__(self):
      return len(self.sentences)
  
imports: from os.path import dirname, join, exists
  from torch.utils.data import Dataset
  from underthesea import pos_tag
  from underthesea import dependency_parse
  from underthesea.utils.col_analyzer import UDAnalyzer
label_desc: Use image node_id 5 for calling the UDDataset obj's underlying member method code with example usage: obj.__len__() and returns: len