Decorator

def shout(func):
    def wrapper():
        result = func()
        return result.upper()
    return wrapper

def greet():
    return 'hello'

loud_greet = shout(greet)
print(loud_greet())   # HELLO

def shout(func):
    def wrapper():
        result = func()
        return result.upper()
    return wrapper

@shout
def greet():
    return 'hello'

print(greet())   # HELLO — @shout স্বয়ংক্রিয়ভাবে apply হয়

import time

def timer(func):
    def wrapper(*args, **kwargs):
        start = time.time()
        result = func(*args, **kwargs)
        print(f'{func.__name__} took {time.time() - start:.4f}s')
        return result
    return wrapper

@timer
def slow_add(a, b):
    time.sleep(1)
    return a + b

slow_add(2, 3)   # print করে: slow_add took 1.0003s