What is meant by 'define model class' in pytorch documentation?

On the pytorch documentation page about saving and loading models, it says that when loading a saved model, # Model class must be defined somewhere Saving and Loading Models — PyTorch Tutorials 1.12.1+cu102 documentation

Maybe my question is silly, but what does class in this context refer to? Thanks in advance.

Earlier on the page, the ‘loading-of-a-model process’ is described such as


model = TheModelClass(*args, **kwargs)