import unittest
 
class TestStatisticalFunctions(unittest.TestCase):
    def test_average(self):
        self.assertEqual(average([20, 30, 70]), 40.0)
        self.assertEqual(round(average([1, 5, 7]), 1), 4.3)
            average([])
        with self.assertRaises(TypeError):
            average(20, 30, 70)
unittest.main()  # Calling from the command line invokes all tests