I am trying to make a physics engine using python turtle. I have a class called Entity, which has parameters shape, for either a square or circle. It has a attribute inside __init__() which is called controller which is just a python Turtle

Lets say I create a instance
my_square = Entity("square"). How can, upon initialisation, my_square be appended to a list of current entities? I really want to avoid using a name parameter, and then adding that.