Install cl-dynamic-classes by entering the following commands in the terminal:
sudo apt update sudo apt install cl-dynamic-classes
Common Lisp Dynamic Classes
Class-mixins are a great idea but sometimes they lead to a proliferation of subclasses with names like printable-touchable-composing-colored-shape-square-mixin and that's just ugly. Common-Lisp is a dynamic-programming language; Dynamic-Classes brings dynamism to class definition!