Metaclasses are powerful but complex. Class decorators offer a simpler way to modify or inspect a class immediately after it is defined.
In this example, the Square class overrides the area method of the Rectangle class. python 3 deep dive part 4 oop
class Order: quantity = PositiveNumber() price = PositiveNumber() Metaclasses are powerful but complex
__slots__ prevents automatic __dict__ creation, saving memory for many instances. saving memory for many instances.