input: Write a function to create a web application in Python using Flask that will take user input and generate an HTML page with the input. The function should define a Flask route for both GET and POST methods and use HTML templates to display the input. If no input is provided, the application should display a default message. If the Flask application is run in debug mode, the function should return True; otherwise, it should return False.
  assert flask_app_creation()==True
  assert flask_app_creation()==False
output: def flask_app_creation():
      from flask import Flask, request, render_template
  
      app = Flask(__name__)
  
      @app.route('/', methods=['GET', 'POST'])
      def index():
          if request.method == 'POST':
              user_input = request.form.get('user_input', 'No input provided')
          else:
              user_input = 'No input provided'
          return render_template('index.html', user_input=user_input)
  
      if __name__ == '__main__':
          app.run(debug=True)
          return True
      return False