def test_list_of_four(self):
     m = median([9, 8, 7, 10])
     self.assertEqual(m, 8.5)
 def test_list_of_three(self):
     m = median([7, 9, 8])
     self.assertEqual(m, 8)
 def test_list_of_one(self):
     m = median([7])
     self.assertEqual(m, 7)
 def test_list_of_two(self):
     m = median([8, 7])
     self.assertEqual(m, 7.5)
 def test_empty_list(self):
     m = median([])
     self.assertIsNone(m)