Quick Check: Python __init_subclass__ and Class Creation Hooks

Review

1. Inside Base.__init_subclass__(cls), what does cls refer to when class Report(Base) is created?

   cls is the newly created subclass, so it is Report in this example.
2. What is a central use of __init_subclass__?

   The hook is called during subclass creation, making it useful for class-level setup and validation.
3. Why should a cooperative __init_subclass__ call super().__init_subclass__(**kwargs)?

   Forwarding unused keyword arguments lets other classes in the customization chain handle their own options.
4. What happens when __init_subclass__ raises an exception while a subclass is being defined?

   An exception from __init_subclass__ stops that class definition from completing successfully.
5. Which distinction is correct?

   __init_subclass__ is inherited by bases and runs for new subclasses; a class decorator operates on the particular class it decorates.