fix failing tests

.github/workflows/python-app.yml

@@ -24,6 +24,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install flake8
+        pip install mglib
         if [ -f requirements/base.txt ]; then pip install -r requirements/base.txt; fi
         sudo apt install poppler-utils pdftk
     - name: Lint with flake8