superset: Error while installing (markdown() takes 1 positional argument but 2 were given)

• [X ] I have checked the superset logs for python stacktraces and included it here as text if any
• [X ] I have reproduced the issue with at least the latest released version of superset
• [X ] I have checked the issue tracker for the same issue and I haven’t found one similar

Superset version

dev and release 0.27.0

Expected results

Installed superset

Actual results

Error while installing: Was unable to import superset Error: markdown() takes 1 positional argument but 2 were given

Steps to reproduce

Followed the instructions for a fresh (docker) installation:

git clone https://github.com/apache/incubator-superset/
cd incubator-superset
cp contrib/docker/{docker-build.sh,docker-compose.yml,docker-entrypoint.sh,docker-init.sh,Dockerfile} .
cp contrib/docker/superset_config.py superset/
bash -x docker-build.sh
docker-compose up -d
docker-compose exec superset bash
bash docker-init.sh

at the last command after the username/usermail/ password are asked for input the installation fails. Reproduced on two different laptops

Additionally, when not using the docker installation. It fails at the same step: fabmanager create-admin --app superset (which is done in the docker installation in the bash docker-init.sh script)

Trace:

xxx@xxx-server:~/dev/compose/incubator-superset$ docker-compose exec superset bash
work@3d443226a074:~/incubator-superset$ bash docker-init.sh
+ fabmanager create-admin --app superset
Username [admin]: xxx
User first name [admin]: xxx
User last name [user]: xxx
Email [admin@fab.org]: xxx@xxx.com
Password: 
Repeat for confirmation: 
Loaded your LOCAL configuration at [/home/work/incubator-superset/superset/superset_config.py]
Was unable to import superset Error: markdown() takes 1 positional argument but 2 were given