gunicorn software package provides Event-based HTTP/WSGI server (Python 2 version), you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gunicorn
gunicorn is installed in your system.
Make ensure the gunicorn package were installed using the commands given below,
$ sudo dpkg-query -l | grep gunicorn *
You will get with gunicorn package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Web Servers |
| Package | gunicorn |
| Version | 19.6.0-8 |
| Description | Event-based HTTP/WSGI server (Python 2 version) |
| Sub Section | httpd |