الـ Decorators

def shout(text):
    return text.upper()

say = shout              # no () -> we pass the function itself
print(say("hello"))

def apply(func, value):  # a function that receives another function
    return func(value)

print(apply(shout, "ahlan"))

import time
from functools import wraps

def timer(func):
    @wraps(func)                       # keeps the original function's name
    def wrapper(*args, **kwargs):
        start = time.time()
        result = func(*args, **kwargs) # call the original function
        elapsed = time.time() - start
        print(f"{func.__name__} took {elapsed:.2f}s")
        return result
    return wrapper

@timer                                 # same as: slow_report = timer(slow_report)
def slow_report():
    time.sleep(1.2)
    return "report ready"

print(slow_report())

current_user = {"name": "Sara", "logged_in": False}

def login_required(func):
    def wrapper(*args, **kwargs):
        if not current_user["logged_in"]:
            print("Please log in first")
            return None
        return func(*args, **kwargs)
    return wrapper

@login_required
def show_orders():
    print(f"Orders for {current_user['name']}: #1024, #1031")

show_orders()
current_user["logged_in"] = True
show_orders()

class Rectangle:
    def __init__(self, width, height):
        self.width = width
        self.height = height

    @property
    def area(self):             # computed, but used like an attribute
        return self.width * self.height

r = Rectangle(4, 5)
print(r.area)                   # no () needed