input: Write a function to create a Flask web application that takes user input via a form, and displays the input on an HTML page. The function should return the Flask application object. If no input is provided, the function should display a default homepage.
  
  def create_flask_app():
      from flask import Flask, render_template, request
      
      app = Flask(__name__)
      
      @app.route('/', methods=['GET', 'POST'])
      def home():
          if request.method == 'POST':
              input_text = request.form.get('input_text')
              return render_template('result.html', input_text=input_text)
          return render_template('index.html')
      
      return app
  
  assert create_flask_app().name == '__main__'
output: def create_flask_app():
      from flask import Flask, render_template, request
      
      app = Flask(__name__)
      
      @app.route('/', methods=['GET', 'POST'])
      def home():
          if request.method == 'POST':
              input_text = request.form.get('input_text')
              return render_template('result.html', input_text=input_text)
          return render_template('index.html')
      
      return app