old_contents: from flask import (render_template, redirect, url_for)
  from flask import session
  from flask_login import (login_required, logout_user)
  
  from app.main import main
  
  
  @main.route('/sign-out', methods=(['GET']))
  @login_required
  def sign_out():
      logout_user()
      return redirect(url_for('main.sign_in'))
  
new_contents: from flask import (render_template, redirect, url_for)
  from flask import session
  from flask_login import (login_required, logout_user)
  
  from app.main import main
  
  
  @main.route('/sign-out', methods=(['GET']))
  @login_required
  def sign_out():
      logout_user()
      return redirect(url_for('main.index'))
  
subject: Update sign_out to go to the index page not sign-in