How can you create a decorator in Python and how to use it?

A decorator in Python is a function that takes another function and returns a new function with extended behavior, without modifying the original code.

You can create a decorator like this:

def decorator(func):
    def wrapper(*args, **kwargs):
        print("Before calling the function")
        result = func(*args, **kwargs)
        print("After calling the function")
        return result
    return wrapper

Using a decorator is convenient with the @ syntax before defining a function:

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

say_hello("World")

The output will be:

Before calling the function
Hello, World!
After calling the function

Thus, decorators allow adding additional logic (such as logging, permission checks, caching) to functions without changing their code.