input: 
  def create_flask_app() -> Flask:
      """Create a 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.
      >>> create_flask_app()
      <Flask 'app'>
      """
  
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)
  
      if __name__ == '__main__':
          app.run(port=5000, debug=True)
  
      return app
  