provoking error

.gitlab-ci.yml

@@ -26,6 +26,8 @@ tests:
         - apt update
         - apt install -y libgl1-mesa-glx xvfb graphviz xdg-utils libcairo2-dev libjpeg-dev libgif-dev
         - pip install tox
+        - which python
+        - ls /usr/lib/python3.7/
         - python -c 'from test.support import swap_attr2'
         - xvfb-run tox -v --recreate