old_contents: import flask
  from donut import constants
  from donut.modules.auth import blueprint
  
  @blueprint.route('/login')
  def login():
      """Display login page."""
      return flask.render_template('login.html')
  
  @blueprint.route('/login/submit', methods=['POST'])
  def login_submit():
      """Handle authentication."""
      # TODO: Add login logic.
      flask.flash('Incorrect username or password. Please try again!')
      return flask.redirect(flask.url_for('auth.login'))
  
  @blueprint.route('/userreg')
  def user_reg():
      return flask.render_template('userreg.html')
  
  @blueprint.route('/userreg/submit', methods = ['POST'])
  def user_reg_submit():
      return ""
  
  @blueprint.route('/recover', methods = ['POST'])
  def recover():
      return ""
  
new_contents: import flask
  from donut import constants
  from donut.modules.auth import blueprint
  
  @blueprint.route('/login')
  def login():
    """Display login page."""
    return flask.render_template('login.html')
  
  @blueprint.route('/login/submit', methods=['POST'])
  def login_submit():
    """Handle authentication."""
    # TODO: Add login logic.
    flask.flash('Incorrect username or password. Please try again!')
    return flask.redirect(flask.url_for('auth.login'))
  
  @blueprint.route('/userreg')
  def user_reg():
    return flask.render_template('userreg.html')
  
  @blueprint.route('/userreg/submit', methods = ['POST'])
  def user_reg_submit():
    return ""
  
  @blueprint.route('/recover', methods = ['POST'])
  def recover():
    return ""
  
subject: Set 2 space indent.