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 __init__(self, transform):
      self.transform = transform
  
      # mapping from each nested field to their proper position
      self.maps = dict()
      # names of each field
      self.keys = set()
      # values of each position
      self.values = []
      for i, field in enumerate(self.transform):
          if not isinstance(field, Iterable):
              field = [field]
          for f in field:
              if f is not None:
                  self.maps[f.name] = i
                  self.keys.add(f.name)
  
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 1 to create a new Sentence object from inherited base classes: object with example: obj = Sentence(transform)