OK, as I can see nothing is enforced but I can use mypy and tests for the purpose. As I am using pycharm, looks like I need a plugin for mypy. There are two of them out there: non official: https://plugins.jetbrains.com/plugin/11086-mypy and official: https://plugins.jetbrains.com/plugin/13348-mypy-official- Do you have any experience with any of these plugins? Please share your opinion. Best regards.