implement type-hints for all our functions

as a first step, we'll ad mypy static analyzer to check those.
This should give us extra (offline) guarantees about those types.

Author: igalic

.gitignore

@@ -18,3 +18,4 @@ venv-*/
 .python-version
 python3.6.core
 man/*.gz
+.mypy_cache/

setup.cfg

@@ -1,6 +1,9 @@
 [metadata]
 description-file = README.md
 
+[mypy]
+python_version = 3.6
+
 [tool:pytest]
 addopts = -v -x -rs --ignore=setup.py --pep8 --cov-report term-missing --cov=libiocage/lib libiocage/lib libiocage/tests
 pep8maxlinelength = 80

setup.py

@@ -64,5 +64,5 @@
         ]
     },
     data_files=_data,
-    tests_require=['pytest', 'pytest-cov', 'pytest-pep8']
+    tests_require=['pytest', 'pytest-cov', 'pytest-pep8', 'mypy']
 )