Naive solution without using built-in libraries
python\nclass Foo:\n    def __init__(self):\n        self.called = 0\n\n    def first(self, printFirst: \'Callable[[], None]\') -> None:\n        while self.cal
```python\nclass Foo:\n    def __init__(self):\n        self.called = 0\n\n    def first(self, printFirst: \'Callable[[], None]\') -> None:\n        while self.called != 0:\n            continue\n        # printFirst() outputs "first". Do not change or remove this line.\n        printFirst()\n        self.called = 1\n\n\n    def second(self, printSecond: \'Callable[[], None]\') -> None:\n        while self.called != 1:\n            continue\n        # printSecond() outputs "second". Do not change or remove this line.\n        printSecond()\n        self.called = 2\n\n\n    def third(self, printThird: \'Callable[[], None]\') -> None:\n        while self.called != 2:\n            continue\n        # printThird() outputs "third". Do not change or remove this line.\n        printThird()\n```\n\nNot sure if it meets the goal of this problem, but it passed..
['Python3']