Server warning

[Tamara Berger]

I created a webapp with flask, but got a warning in terminal when I tested it.

Last login: Sat Jun 16 01:13:28 on ttys000
192:~ TamaraB$ cd Desktop/Webapp
192:Webapp TamaraB$ python3 hello_flask.py
 * Serving Flask app "hello_flask" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

Is this a serious issue, or can I ignore it? I was just following
instructions in a manual I consider trustworthy.

Thanks,

Tamara