Can you explain how to implement a decorator that does not use parameters?

A parameterless decorator is a function that takes another function and returns a new function with additional behavior. Here's an example of a simple decorator that prints a message before calling the function:

def simple_decorator(func):
    def wrapper(*args, **kwargs):
        print("Calling function...")
        return func(*args, **kwargs)
    return wrapper

@simple_decorator
def say_hello(name):
    print(f"Hello, {name}!")

say_hello("World")

Here, simple_decorator does not take any parameters other than the function it decorates. Inside, a nested function wrapper is created, which adds the desired behavior and calls the original function.