input: Write a function to create a web application using Flask that takes user input and generates an HTML page displaying the input. If the input is received via a POST request, display the input on the result page. If no input is received, render the default index page. Use Flask's built-in methods to handle the routing and rendering of templates.
  assert create_flask_app()==<Flask 'app'>
  assert render_index_page()=="""<html>
   <body>
    <h1>Your Input: </h1>
    <p>{{input_text}}</p>
   </body>
  </html>"""
  assert handle_form_post()=="""<html>
   <body>
    <h1>Your Input: </h1>
    <p>TestInput</p>
   </body>
  </html>"""
  assert handle_form_get()==<Flask 'app'>
output: 
  from flask import Flask, render_template, request
  
  app = Flask(__name__)
  
  @app.route('/', methods=['GET', 'POST'])
  def index():
      if request.method == 'POST':
          user_input = request.form['input_text']
          return render_template('result.html', input_text=user_input)
      return render_template('index.html')
  