In this chapter, we learned that design patterns are useful abstractions that provide "best practice" solutions for common programming problems. We covered our first design pattern, the iterator, as well as numerous ways that Python uses and abuses this pattern for its own nefarious purposes. The original iterator pattern is extremely object-oriented, but it is also rather ugly and verbose to code around. However, Python's built-in syntax abstracts the ugliness away, leaving us with a clean interface to these object-oriented constructs.
Comprehensions and generator expressions can combine container construction with iteration in a single line. Generator objects can be constructed using the yield syntax. Coroutines look like generators on the outside but serve a much different purpose.
We'll cover several more design patterns in the next two chapters.
