input: Write a function named create_web_app to create a Flask web application that takes user input via a form and generates an HTML page displaying the input. The function should return the Flask app object. The web application should have a home route that handles both GET and POST requests, rendering an index.html template for GET requests and a result.html template for POST requests, which displays the user's input.
  
  assert create_web_app() != None
  assert create_web_app().config['DEBUG'] == True
output: from flask import Flask, request, render_template
  
  def create_web_app():
      app = Flask(__name__)
      app.config['DEBUG'] = True
  
      @app.route('/', methods=['GET', 'POST'])
      def home():
          if request.method == 'POST':
              user_input = request.form['user_input']
              return render_template('result.html', user_input=user_input)
          return render_template('index.html')
  
      return app