code: def __init__(self, doc="", tokens=None):
      self.doc = doc
      if tokens is not None and len(tokens) > 0:
          self.tokens = self.token2obj(tokens)
      else:
          self.tokens = []
      self.changed_cnt = 0
  
file_path: nlpaug/nlpaug/util/doc/doc.py
imports: from nlpaug.util.doc.token import Token
  from nlpaug.util.doc.change_log import ChangeLog
label_desc: Use image node_id 1 to create a new Doc object  with example: obj = Doc(doc, tokens)