Advanced syntax

It is hard to objectively tell which element of language syntax is advanced. For the purpose of this chapter, we will consider advanced syntax elements to be the elements that do not directly relate to any specific built-in datatypes, and which are relatively hard to grasp in the beginning. The most common Python features that may be hard to understand are the following:

• Iterators
• Generators
• Decorators
• Context managers

Iterators

An iterator is nothing more than a container object that implements the iterator protocol. This protocol consists of two methods:

• __next__: This returns the next item of the container
• __iter__: This returns the iterator itself

Iterators can be created from a sequence using the iter...