An example that beginners would be likely to be inspired by. It wouldn't have been much harder to write a single line of
render_template('something.html')
and then write the HTML for the template in a separate code section.
render_template('something.html')
and then write the HTML for the template in a separate code section.
Anything else is a distraction.
Using render_template would have left us wondering whether there was anything relevant to the task in render_template, or at best interrupting the reader's flow.
render_template('error.html')