A real-life example
The fact that the pattern is called Decorator does not mean that it should be used only for making things look prettier. The Decorator pattern is generally used for extending the functionality of an object. Real examples of such extensions are: adding a silencer to a gun, using different camera lenses (in cameras with removable lenses), and so on.
The following figure, provided by sourcemaking.com, shows how we can decorate a gun with special accessories to make it silent, more accurate, and devastating [j.mp/decopat]. Note that the figure uses sub-classing, but in Python, this is not necessary because we can use the built-in decorator feature of the language.
