Comprehensions
We've already seen a lot of Python's for loop. It allows us to loop over any object that supports the iterable protocol and do something specific with each of the elements in turn.
Supporting the iterable protocol simply means an object has an __iter__ method that returns another object that supports the iterator protocol. Supporting the iterator protocol is a fancy way of saying it has a __next__ method that either returns the next object in the sequence, or raises a StopIteration exception when all objects have been returned.
As you can see, the for statement, in spite of not looking terribly object-oriented, is actually a shortcut to some extremely object-oriented designs. Keep this in mind as we discuss comprehensions, as they, ...
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