old_contents: from flask import Flask, request, redirect, session
  import twilio.twiml
  
  # The session object makes use of a secret key.
  SECRET_KEY = 'a secret key'
  app = Flask(__name__)
  app.config.from_object(__name__)
  
  # Try adding your own number to this list!
  callers = {
      "+14158675309": "Rey",
      "+14158675310": "Finn",
      "+14158675311": "Chewy",
  }
  
  @app.route("/", methods=['GET', 'POST'])
  def hello():
      """Respond with the number of text messages sent between two parties."""
  
      counter = session.get('counter', 0)
  
      # increment the counter
      counter += 1
  
      # Save the new counter value in the session
      session['counter'] = counter
  
      from_number = request.values.get('From')
      if from_number in callers:
          name = callers[from_number]
      else:
          name = "Friend"
  
      message = "".join([name, " has messaged ", request.values.get('To'), " ", 
          str(counter), " times."])
      resp = twilio.twiml.Response()
      resp.message(message)
  
      return str(resp)
  
  if __name__ == "__main__":
      app.run(debug=True)
new_contents: from flask import Flask, request, session
  from twilio import twiml
  
  # The session object makes use of a secret key.
  SECRET_KEY = 'a secret key'
  app = Flask(__name__)
  app.config.from_object(__name__)
  
  # Try adding your own number to this list!
  callers = {
      "+14158675309": "Rey",
      "+14158675310": "Finn",
      "+14158675311": "Chewy",
  }
  
  @app.route("/", methods=['GET', 'POST'])
  def hello():
      """Respond with the number of text messages sent between two parties."""
      # Increment the counter
      counter = session.get('counter', 0)
      counter += 1
  
      # Save the new counter value in the session
      session['counter'] = counter
  
      from_number = request.values.get('From')
      if from_number in callers:
          name = callers[from_number]
      else:
          name = "Friend"
  
      # Build our reply
      message = '{} has messaged {} {} times.' \
          .format(name, request.values.get('To'), counter)
  
      # Put it in a TwiML response
      resp = twiml.Response()
      resp.message(message)
  
      return str(resp)
  
  if __name__ == "__main__":
      app.run(debug=True)
  
subject: Clean up Python example for sms-conversation-tracking