black (#445)

HACKING.md

@@ -36,7 +36,7 @@ Future `git` commits will now invoke these hooks automatically.
 
 ## Coding style
 
-We try to get as close as the [PEP8 code convention](http://legacy.python.org/dev/peps/pep-0008/) as is reasonable without being dumb. If you use Vim, the [python-mode](https://github.com/klen/python-mode) plugin does all you need. You can also [manually configure](https://wiki.python.org/moin/Vim) vim to adopt this behavior.
+We format our code with [black](https://github.com/psf/black) and otherwise try to get as close as the [PEP8 code convention](http://legacy.python.org/dev/peps/pep-0008/) as is reasonable without being dumb. If you use Vim, the [python-mode](https://github.com/klen/python-mode) plugin does all you need. You can also [manually configure](https://wiki.python.org/moin/Vim) vim to adopt this behavior.
 
 Most importantly, please consider the following when writing code as part of angr:
 
@@ -54,6 +54,8 @@ Most importantly, please consider the following when writing code as part of ang
 
 * Always use `_` instead of `__` for private members \(so that we can access them when debugging\). _You_ might not think that anyone has a need to call a given function, but trust us, you're wrong.
 
+* Format your code with `black`; config is already defined within `pyproject.toml`.
+
 ## Documentation
 
 Document your code. Every _class definition_ and _public function definition_ should have some description of: