Python 3 Deep Dive Part 4 Oop Guide

By default, Python stores instance attributes in a dictionary (__dict__), which consumes extra memory. For thousands of instances, __slots__ can drastically reduce memory usage:

class Point:
    __slots__ = ('x', 'y')  # No __dict__ per instance
    def __init__(self, x, y):
        self.x = x
        self.y = y

Benefits:

Drawback:

class Multiplier:
    def __init__(self, factor):
        self.factor = factor
def __call__(self, value):
        return value * self.factor
double = Multiplier(2)
print(double(5)) # Output: 10

Use @abstractmethod with @classmethod, @staticmethod, @property. python 3 deep dive part 4 oop