Basic Flask web app

 from flask import Flask

app = Flask(__name__)

#In Flask, URL rules can be added using either the @app.route() decorator or the app.add_url_rule() method.

@app.route('/')

def hello_world():

   return '<center><h1><I>Hello World</I></h1></center>'

def bye_world():

   return '<center><h1><I>Bye World</I></h1></center>'

app.add_url_rule('/bye', 'bye', bye_world)

if __name__ == "__main__":

   app.run(debug = True)