ci: type checking in Python workflow

.github/workflows/python-package.yml

@@ -26,7 +26,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        python -m pip install flake8 pytest
+        python -m pip install flake8 pytest mypy
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
         
         python -m pip install build
@@ -38,6 +38,9 @@ jobs:
         python -m flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
         python -m flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+    - name: Type check with MyPy
+      run: |
+        python -m mypy wonderwords
     - name: Test with pytest
       run: |
         python -m pytest