The values may contain None which is not orderable so we insert a third
argument before the value to prevent to compare None value against others.
issue9381
review303881005
We add the flake8 configuration used so we ensure everyone uses the same.
We remove the usage of __all__ for non public API.
When possible, we rationalize the class name according to its __name__ and module.
issue9082
review297061002
In Python3, ordering None value is no more allowed.
We add a second line to the scenario to really test the ordering otherwise the
key function is not called.
issue7441
review53311002
Cédric Krier