new_contents: from __future__ import unicode_literals
  from ...tokens import Doc
  from ...vocab import Vocab
  
  
  def test_issue1834():
      """test if sentence boundaries & parse/tag flags are not lost
      during serialization
      """
      words = "This is a first sentence . And another one".split()
      vocab = Vocab()
      doc = Doc(vocab, words=words)
      vocab = doc.vocab
      doc[6].sent_start = True
      deser_doc = Doc(vocab).from_bytes(doc.to_bytes())
      assert deser_doc[6].sent_start
      assert not deser_doc.is_parsed
      assert not deser_doc.is_tagged
      doc.is_parsed = True
      doc.is_tagged = True
      deser_doc = Doc(vocab).from_bytes(doc.to_bytes())
      assert deser_doc.is_parsed
      assert deser_doc.is_tagged
  
  
  
  
  
subject: add test for the issue