As a class

While decorators can almost always be implemented using functions, there are some situations when using user-defined classes is a better option. This is often true when the decorator needs complex parameterization, or if it depends on a specific state.

The generic pattern for a non-parameterized decorator defined as a class is as follows:

class DecoratorAsClass: 
    def __init__(self, function): 
        self.function = function 
 
    def __call__(self, *args, **kwargs): 
        # do some stuff before the original 
        # function gets called 
        result = self.function(*args, **kwargs) 
        # do some stuff after function call and 
        # return the result 
        return result