As part of a concerted effort to add type annotations to wazo python code, a zuul job should be created to enable some automated type-checking in CI.

• mypy is the state-of-the-art type checker where much of the evolution of python typing happens as extensions before being included in core python, so should be a good default choice

• incremental typing should be supported, so that only existing type annotations are checked and validated while untyped code is ignored. Other configuration could also be considered to disable some failure modes/add support for some patterns.

A failure to type check for typed code should be considered a bug that needs to be fixed before approval and merge.
The type check command can be encapsulated into a tox target(“environment”), allowing local development workflow and per-repo customization(if necessary). The job implementation should then be similar to other tox-based jobs(`wazo-tox-*`).