old_contents: #!/usr/bin/env python
  import os
  from flask import Flask
  from flask.ext.pymongo import PyMongo
  
  
  CONFIGS = (
      'AUTH_TOKEN',
      'CELL_NUM',
      'MONGOLAB_URI',
      'TWILIO_NUM',
  )
  
  
  # Set up the app
  app = Flask(__name__)
  app.config.update(**{v: os.environ[v] for v in CONFIGS})
  app.config['MONGO_URI'] = app.config['MONGOLAB_URI']  # for flask-pymongo
  
  
  # Initialize extensions
  pymongo = PyMongo(app)
  
  
  @app.route('/')
  def home():
      return "yo"
  
  
  if __name__ == '__main__':
      app.run(debug=True)
  
new_contents: #!/usr/bin/env python
  import os
  from flask import Flask
  from flask.ext.pymongo import PyMongo
  
  
  CONFIGS = (
      'AUTH_TOKEN',
      'CELL_NUM',
      'MONGOLAB_URI',
      'TWILIO_NUM',
  )
  
  
  # Set up the app
  app = Flask(__name__)
  app.config.update(**{v: os.environ[v] for v in CONFIGS})
  app.config['MONGO_URI'] = app.config['MONGOLAB_URI']  # for flask-pymongo
  
  
  # Initialize extensions
  pymongo = PyMongo(app)
  
  
  def check_in(phone_number, code):
      """Check in (and possibly create) a user, verified by the active code.
  
      Returns the user's data, or None if the code is wrong.
  
      The correct code is currently hard-coded to ABC.
      """
      user_data = {
          'phone_number': phone_number
      }
      return user_data if code == 'ABC' else None
  
  
  @app.route('/')
  def home():
      return "yo"
  
  
  if __name__ == '__main__':
      app.run(debug=True)
  
subject: add a check-in stub