Summary

In this chapter, we went into detail on several more design patterns, covering their canonical descriptions as well as alternatives for implementing them in Python, which is often more flexible and versatile than traditional object-oriented languages. The adapter pattern is useful for matching interfaces, while the facade pattern is suited to simplifying them. Flyweight is a complicated pattern and only useful if memory optimization is required. In Python, the command pattern is often more aptly implemented using first class functions as callbacks. Abstract factories allow run-time separation of implementations depending on configuration or system information. The composite pattern is used universally for tree-like structures.

In the next chapter, we'll discuss how important it is to test Python programs, and how to do it.