def log(text=''):
    def decorator(func):
        def wrapper(*args, **kw):
            print('%s %s():' % (text, func.__name__))
            return func(*args, **kw)
        return wrapper
    return decorator

@log()
def power(x,y=2):
    return x**y

@log('I can enter')
def dpower(x,y=2):
    return x**y