the models repository is a subclass of a dictionary object which keeps track of model objects. As explained before, a subclass means that it has the same properties and methods of the dictionary object along with a few more properties and methods, such as cbaogeKeyQ, that developers at SIMULIA decided to add in. The model name 'Model- I' is the key, while the value is a model object. The changeKeyO method which is not native to Python essentially allows us to change the key to 'Cantilever Beam' while referring to the same model object.