The following Python code intends to enforce that all `Worker` subclasses implement a `work` method. However, it's not working as expected. class Worker:     def work(self):         raise NotImplementedError("Subclasses must implement this method") class Engineer(Worker):     pass eng = Engineer() eng.work() What is the most Pythonic way to fix this to ensure `Engineer` *must* implement `work` at compile/definition time?

Solution

o The original Worker class uses NotImplementedError, which is a runtime check. The error only occurs when eng.work() is actually called. o To enforce that Engineer must implement work at the time the Engineer class is defined (or instantiated), you need to use Python's Abstract Base Classes (ABCs). o By inheriting Worker from abc.ABC and decorating work with @abstractmethod, Worker becomes an abstract class. Any concrete subclass (like Engineer) that fails to implement work will raise a TypeError when you try to instantiate it (e.g., eng = Engineer()).