old_contents: """sample test"""
  import unittest
  
  from hello import hello
  
  
  class TestHello(unittest.TestCase):
      """sample test"""
  
      def test_world(self):
          """sample test"""
          self.assertEqual(hello('world'), 'hello world')
  
      def test_world_bytes(self):
          """sample test with bytes"""
          self.assertEqual(hello(b'world'), b'hello world')
  
      def test_world_unicode(self):
          """sample test with unicode"""
          self.assertEqual(hello(u'world'), u'hello world')
  
new_contents: """sample test"""
  import unittest
  
  from hello import hello
  
  
  class TestHello(unittest.TestCase):
      """sample test"""
  
      def test_world(self):
          """sample test"""
          self.assertEqual(hello('world'), 'hello world')
  
      def test_world_unicode(self):
          """sample test with unicode"""
          self.assertEqual(hello(u'world'), u'hello world')
  
subject: remove byte test. it does not work on py3