then, also as root:
- echo 'APT::Default-Release "stable";' | tee -a /etc/apt/apt.conf.d/00local
+ echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
sudo apt-get update
apt-get -t testing install python3.7 python3-setuptools \
python3-jinja2 python3-pip