old_contents: #!/usr/bin/env python
  """
  Example for Facebook Python SDK
  Author: Colin Su <littleq0903@gmail.com>
  """
  from bottle import Bottle, run, template
  from bottle import static_file
  from bottle import jinja2_template
  import facebook
  
  import os
  
  # added a file "settings.py", which contains variables named:
  # - FACEBOOK_APP_ID
  # - FACEBOOK_SECRET
  from settings import FACEBOOK_APP_ID, FACEBOOK_SECRET
  
  # WSGI handler
  app = Bottle()
  
  # Checkpoint 0
  @app.route('/login')
  def login():
      template_data = {
          'facebook_app_id': FACEBOOK_APP_ID
      }
      return jinja2_template('index.html', **template_data)
  
  
new_contents: #!/usr/bin/env python
  """
  Example for Facebook Python SDK
  Author: Colin Su <littleq0903@gmail.com>
  """
  from bottle import Bottle, run, template
  from bottle import static_file
  from bottle import jinja2_template
  import facebook
  
  import os
  
  # setup these environment variable by adding "heroku.config"
  # - FACEBOOK_APP_ID
  # - FACEBOOK_SECRET
  FACEBOOK_APP_ID = os.environ['FACEBOOK_APP_ID']
  FACEBOOK_SECRET = os.environ['FACEBOOK_SECRET']
  
  # WSGI handler
  app = Bottle()
  
  # Checkpoint 0
  @app.route('/login')
  def login():
      template_data = {
          'facebook_app_id': FACEBOOK_APP_ID
      }
      return jinja2_template('index.html', **template_data)
  
  
subject: load env instead of loading settings.py