Explain the use of decorators in Python.

A decorator is a special type of function in Python that is used to modify or extend the behavior of another function, method, or class. They are often used to add additional functionality to existing functions or classes, such as logging, timing, or access control.

In Python, decorators are applied to functions or classes using the "@" symbol, followed by the name of the decorator function. For example: 

When you run this code, calling the 'say_hello()' function will first print "Something is happening before the function is called", then "Hello!", and then "Something is happening after the function is called".

Decorators can also accept arguments and preserve the original function's metadata, such as its name, docstring, and arguments.

The use of decorators provides a convenient and reusable way to add additional functionality to your functions and classes, making your code cleaner and more maintainable.