input: 
  def create_flask_app() -> Flask:
      """
      Create a Python Flask app that listens for POST requests on the '/webhook' route. 
      When a request is received, extract the necessary parameters from the request 
      and call the 'makeWebhookResult' function to generate a response. The response 
      should be a JSON object containing a 'speech' field with the text to be spoken 
      by the voice assistant. The app should be started on port 5000 and run in debug mode.
  
      >>> app = create_flask_app()
      >>> app.run(debug=True, port=5000, host='0.0.0.0')
      "Starting app on port 5000"
      """
  
output:     
      app = Flask(__name__)
  
      @app.route('/webhook', methods=['POST'])
      def webhook():
          req = request.get_json(silent=True, force=True)
          result = makeWebhookResult(req)
          return jsonify(result)
  
      return app
  