existing class with a set of specific features using multiple inheritance. `huggingface_hub` provides its own mixin,
the [`ModelHubMixin`]. The key here is to understand its behavior and how to customize it.  
The [`ModelHubMixin`] class implements 3 *public* methods (`push_to_hub`, `save_pretrained` and `from_pretrained`). Those
are the methods that your users will call to load/save models with your library. [`ModelHubMixin`] also defines 2