class_docstr: A Sentence object holds a sentence with regard to specific data format.
class_docstr_tok: ["A","Sentence","object","holds","a","sentence","with","regard","to","specific","data","format","."]
code: def __len__(self):
      return len(self.values[0])
  
imports: from collections.abc import Iterable
  import nltk
  from tqdm import tqdm
  from underthesea.utils.sp_parallel import is_master
label_desc: Use image node_id 2 for calling the Sentence obj's underlying member method code with example usage: obj.__len__() and returns: len