I've got a local Python application configured with
Under dev_appserver, runtime:python is not supported for Flexible environment.
Using the Local Development Server is applicable to the standard environment apps only.
For running locally flexible env apps see Running locally:
You run your application locally with the native development tools that you usually use.
For example, you can usually run a Flask application with Flask's development server using:
Django applications can be started using:
python manage.py runserver