how to host python web application on heroku code example

Example 1: heroku requirements.txt python

Flask==0.8
Jinja2==2.6
Werkzeug==0.8.3
certifi==0.0.8
chardet==1.0.1
distribute==0.6.24
gunicorn==0.14.2
requests==0.11.1

Example 2: heroku python heroku port issue

import os 
port = int(os.environ.get('PORT', 33507))  # add these lines in code
app.run(host=args.host, port=port, debug=True)  

heroku config:add PORT=33507   # run this command once you upadte the code in terminal