Decorator

`decorator.py`


def print_info(func):
    def wrapper(*args, **kwargs):
        print('start')
        result = func(*args,**kwargs)
        print('end')
        return result
    return wrapper

#Useful when adding something to a function (be careful in order when applying multiple decorators)
@print_info
def add_num(a, b):
    return a+b

r = add_num(10,20)
print(r)
#If you don't use a decorator, you can write as below, but it's hard to understand
#f = print_info(add_num)
#r = f(10,20)
#print(r)

output:

start
end
30