Increment type hints and add mypy

[avara1986]

Add more Python type hints and add mypy valitations. This validation could be a step in GH actions or tox

You can learn more about type hints in this link

Mypy has a command line checker:

mypy pyms

Ideally, mypy must return 0 errors, but could be a hard work because pyms create dynamic attributes.

[ooigavin]

Hi @avara1986 would like to pick this one up!

[avara1986]

Thank you @ooigavin ! ^^ Don't forget to register in https://hacktoberfest.digitalocean.com/ :+1:

[mbcaldeiro]

Quisiera recoger esta issue