This app differs from the Example 1 app in only one respect: It uses a base template (in the templates folder), allowing the two other templates (index.html and student.html) to be very short, relying on the HTML in base.html.
This Flask app, using templates, is explained in the README in flask/part3_templates.
To run it (assuming you are in a Python 3 virtualenv with Flask installed):
python students2.py