Chapter 4 Model objects

• some explanation of why and how to save the function call

• generally what kinds of things should go into a model object, giving model objects a class so other people can extend them

• S3 object creation and validation for model building a la Advanced R

• Model classes beyond lists. when is S4 worth it? when is R6?

• Every modeling function should include its package version in its data object I will now save my models as a list of three objects: model, data, and sessioninfo::session_info()