def test_equal_1(self):
     self.assertEqual(common_ground(
         'eat chicken', 'eat chicken and rice'
     ), 'eat chicken')
 def test_equal_9(self):
     self.assertEqual(common_ground('', 'cc dd'), 'death')
 def test_equal_10(self):
     self.assertEqual(common_ground('', ''), 'death')
 def test_equal_8(self):
     self.assertEqual(common_ground('aa bb', ''), 'death')
 def test_equal_6(self):
     self.assertEqual(common_ground('aa bb cc', 'bb cc bb aa'), 'bb cc aa')
 def test_equal_5(self):
     self.assertEqual(common_ground('aa bb cc', 'bb cc'), 'bb cc')
 def test_equal_3(self):
     self.assertEqual(common_ground(
         'i like turtles', 'what are you talking about'
     ), 'death')
 def test_equal_2(self):
     self.assertEqual(common_ground(
         'eat a burger and drink a coke', 'drink a coke'
     ), 'drink a coke')