I’m a big fan of Jupyter Notebooks. We are creating a product where we interact with the Python code of our users and we would like to add Notebook serving to the product, adding some functions specific to our platform to the Notebooks. This would include a custom theme, some “fixed” cells at the top, some additional buttons and mounting some files to the server. Is there a guide on how to approach (some parts of) this? If not, what is the best way to starting figuring this out?