How to use the icontract._checkers._walk_decorator_stack function in icontract

def test_with_single_decorator(self) -> None:
        @decorator_plus_1
        def func() -> int:
            return 0

        self.assertListEqual([1, 0], [a_func() for a_func in icontract._checkers._walk_decorator_stack(func)])

def test_with_double_decorator(self) -> None:
        @decorator_plus_2
        @decorator_plus_1
        def func() -> int:
            return 0

        self.assertListEqual([3, 1, 0], [a_func() for a_func in icontract._checkers._walk_decorator_stack(func)])

def test_wo_decorators(self) -> None:
        def func() -> int:
            return 0

        self.assertListEqual([0], [a_func() for a_func in icontract._checkers._walk_decorator_stack(func)])