Python 3 code for the book *Artificial Intelligence: A Modern Approach.*

We default to [Pep 8](https://www.python.org/dev/peps/pep-0008), but with a few exceptions:

- I'm not too worried about an occasional line longer than 79 characters.

- You don't need two spaces after a sentence-ending period.

- Strunk and White is [not a good guide for English](http://chronicle.com/article/50-Years-of-Stupid-Grammar/25497).

- I prefer more concise docstrings; I don't follow [Pep 257](https://www.python.org/dev/peps/pep-0257/).

- Not all constants have to be UPPERCASE.

- [Pep 484](https://www.python.org/dev/peps/pep-0484/) type annotations are allowed but not required. If your

parameter name is already suggestive of the name of a type, you don't need an annotation, e.g.:

def retry(url: Url) -> None: # This 'Url' annotation should be avoided; but '-> None' is useful

Are we right to concentrate on Java and Python versions of the code?

What languages do students already know? The [TIOBE Index](http://www.tiobe.com/tiobe_index) says the top five are:

Java, C, C++, C#, Python

What languages are instructors recommending for their AI class?

To get an approximate

<tr><th>Language<th>2004<th>2005<th>2007<th>2010<th>2016