old_contents: from unittest import TestCase
  from unittest.mock import patch, MagicMock
  from meetup_facebook_bot.models import talk
  
  class TalkTestCase(TestCase):
  
      def test_is_liked_by(self):
          pass
  
      def test_set_like(self):
          pass
  
      def test_unset_like(self):
          pass
  
      def test_revert_like(self):
          pass
new_contents: from unittest import TestCase
  from unittest.mock import patch, MagicMock
  from meetup_facebook_bot.models.talk import Talk
  
  class TalkTestCase(TestCase):
  
      def setUp(self):
          self.db_session = MagicMock()
          self.user_id = 1
          self.talk_id = 1
  
  
      def test_is_liked_by(self):
          pass
  
  
      @patch('meetup_facebook_bot.models.talk.Like')
      def test_set_like(self, like_class_mock):
          talk = Talk(id=self.talk_id)
          mock_like = MagicMock()
          like_class_mock.return_value = mock_like
          talk.is_liked_by = MagicMock(return_value=False)
          talk.set_like(self.user_id, self.db_session)
          like_class_mock.assert_called_once_with(user_facebook_id=self.user_id, talk_id=self.talk_id)
          self.db_session.add.assert_called_once_with(mock_like)
  
      def test_unset_like(self):
          talk = Talk(id=self.talk_id)
          talk.is_liked_by = MagicMock(return_value=True)
          like_mock = MagicMock()
          scalar_mock = MagicMock(return_value=like_mock)
          self.db_session.query().filter_by().scalar = scalar_mock
          talk.unset_like(self.user_id, self.db_session)
          self.db_session.delete.assert_called_once_with(like_mock)
subject: Add unset_like test