Add type hints and run mypy

[mmaslowskicc]

Fixes #20.

[codecov]

Codecov Report

Merging #23 (42690ac) into master (c3f0b67) will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #23      +/-   ##
==========================================
+ Coverage   96.65%   96.73%   +0.08%     
==========================================
  Files           8        8              
  Lines         269      276       +7     
==========================================
+ Hits          260      267       +7     
  Misses          9        9              

Flag	Coverage Δ
linux	89.85% <98.55%> (+0.26%)	⬆️
macos	96.01% <100.00%> (+0.10%)	⬆️

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Impacted Files	Coverage Δ
port_for/__init__.py	100.00% <100.00%> (ø)
port_for/api.py	96.25% <100.00%> (+0.09%)	⬆️
port_for/ephemeral.py	91.42% <100.00%> (+0.25%)	⬆️
port_for/store.py	94.23% <100.00%> (-0.11%)	⬇️
port_for/utils.py	100.00% <100.00%> (ø)
tests/test_cases.py	100.00% <100.00%> (ø)

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[mmaslowskicc]

Looks like something before 0.4.1. If we use current docopt and the types-docopt package, we would get its annotation. I don't know any reason for bundling it now.

[fizyk]

well.. me neither. Maybe it was to limit the needed dependencies to bare none by then 🤔
I suppose I could use click for that, but we can migrate to the dependency I suppose. The codebase wasn't refreshed since 2012 (except for black) and future python versions might require unintended changes that will have to be tested (and it's not something I'd like to do)