def test_double_palindromes(self):
self.assertTrue([1], double_palindromes(2))
self.assertTrue([1, 3], double_palindromes(4))
self.assertTrue([1, 3, 5], double_palindromes(6))
self.assertTrue([1, 3, 5, 7, 9], double_palindromes(10))
self.assertTrue([1, 3, 5, 7, 9, 33, 99], double_palindromes(100))
self.assertTrue(585 in double_palindromes(586))
def test_project_euler(self):
self.assertEqual(sum(double_palindromes(1000000)), 872187)