[Feature] Type hints or external stubs

[RichardFevrier]

Hi @kvesteri, please consider adding type hints or an external library stubs to make mypy (or other type checker) to be happy.
Thanks for your work 🙏

[RichardFevrier]

Thanks for your commit/merge @joe733 😌
Please also consider to add a py.typed to make it compliant with the PEP-561