def test_equals(self):
     self.assertEqual(filter_list([1, 2, 'a', 'b']), [1, 2])
 def test_equals_2(self):
     self.assertEqual(filter_list([1, 'a', 'b', 0, 15]), [1, 0, 15])
 def test_equals_3(self):
     self.assertEqual(filter_list([1, 2, 'aasf', '1', '123', 123]),
                      [1, 2, 123])