add mypy checking

also added some .pyi files needed to check the cython code (taken from #5703 and updated).

fixed "syntax error" in key.py.

all mypy complaints not fixed yet.

1 files changed, 8 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 37ed3b142..861c24322 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,3 +29,11 @@ changedir =
 deps =
     flake8
 commands = flake8 src scripts conftest.py
+
+[testenv:mypy]
+changedir =
+deps =
+    pytest
+    mypy
+    pkgconfig
+commands = mypy