PCAP Object-Oriented Programming Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  It automatically provides a default implementation for a method.

  Why it's wrong here

  The @abstractmethod decorator does not supply any implementation; it marks a method as intentionally lacking a concrete body in the abstract base class. A true default implementation would be written as a normal method with code and then optionally overridden, but an abstract method is declared precisely because no meaningful default exists. When a subclass fails to override it, the class remains abstract and cannot be instantiated, so no default behavior is ever provided.

• ✓

  It indicates that a method must be overridden in any non-abstract subclass.

  Why this is correct

  Decorating a method with @abstractmethod registers it in the class's __abstractmethods__ set, and the ABCMeta metaclass enforces that every concrete (non-abstract) subclass must provide an overriding implementation. This enforcement happens at instantiation time: attempting to create an instance of a subclass that leaves any abstract method unimplemented raises TypeError. Thus the decorator expresses a contract that subclasses must fulfill, not a prefix to an automatically inherited implementation.

• ✗

  It creates a method that can be called without an instance.

  Why it's wrong here

  A method callable without an instance is the effect of @staticmethod or @classmethod, both of which bind the method to the class rather than to an instance. In contrast, an abstract method is an ordinary instance method; it still expects self as its first parameter and becomes callable only after a concrete subclass overrides it, at which point an instance is required. Confusing @abstractmethod with static or class decorators overlooks the role of self and the instantiation contract.

• ✗

  It raises AttributeError if the method is called.

  Why it's wrong here

  Calling an abstract method directly does not raise AttributeError; if the method is somehow reached, its body typically contains pass or raises NotImplementedError, so a call would return None or raise that explicit exception. The real TypeError raised by @abstractmethod occurs earlier, when code tries to instantiate a class whose __abstractmethods__ set is non-empty, not when the method itself is invoked. AttributeError would indicate a missing attribute entirely, which is not how Python resolves inheritable method names.

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