In this chapter, we have learned how to use the Facade pattern. This pattern is ideal for providing a simple interface to client code that wants to use a complex system but does not need to be aware of the system's complexity. A computer is a Facade, since all we need to use it is to press a single button for turning it on. All the rest hardware complexity is handled transparently by the BIOS, the boot loader, and the rest system software. There are more real-life examples of Facade, such as when we are connected to the customer service department of a bank, or a company, and the keys that we use to turn a vehicle on.

We discussed two Django third-party modules that use Facade: django-oscar-datacash and Caliendo. The first uses the Facade pattern to provide a simple DataCash API, and the ability to save transactions. The latter uses Facade for different purposes, like caching and deciding what should be returned based on the type of the input object.

We covered the basic use cases...