The python has the decorator decorator reference (c)

No reference decorator:

When invoked with no parameters decorator, the outer layer does not need to pass parameters.

It applies, for example:

　　- Increase uptime statistics function is a function

　　- Increase login authentication function is a function before running

There are parameters decorator:

When calling parameters have decorator, passing them one or more parameters.

It applies, for example:

　　- verify that the user types

def user_auth(user_group):
    def wrapper(func):
        def inner(*args, **kwargs):
            if user_group == 'SVIP':
                print('Dear SVIP')
                res = func(*args, **kwargs)
                return res

            elif user_group == 'General':
                res = func(*args, **kwargs)
                return res

            else:
                print('Please login first!')
                login()

        return inner

    return wrapper


@user_auth(user_group='SVIP')
def welcome():
    print('Welcome to the index')


welcome()