old_contents: '''Test comparison against None doesn't cause segfault'''
  from __future__ import unicode_literals
  
  from ...tokens import Doc
  from ...vocab import Vocab
  
  def test_issue1757():
      doc = Doc(Vocab(), words=['a', 'b', 'c'])
      assert not doc[0] < None
      assert not doc[0] == None
      assert doc[0] >= None
      span = doc[:2]
      assert not span < None
      assert not span == None
      assert span >= None
      lex = vocab['a']
      assert not lex == None
      assert not lex < None
  
new_contents: '''Test comparison against None doesn't cause segfault'''
  from __future__ import unicode_literals
  
  from ...tokens import Doc
  from ...vocab import Vocab
  
  def test_issue1757():
      doc = Doc(Vocab(), words=['a', 'b', 'c'])
      assert not doc[0] < None
      assert not doc[0] == None
      assert doc[0] >= None
      span = doc[:2]
      assert not span < None
      assert not span == None
      assert span >= None
      lex = doc.vocab['a']
      assert not lex == None
      assert not lex < None
  
subject: Fix test