old_contents: #    Copyright 2016 Mirantis, Inc.
  #
  #    Licensed under the Apache License, Version 2.0 (the "License"); you may
  #    not use this file except in compliance with the License. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  #    License for the specific language governing permissions and limitations
  #    under the License.
  
  from flask import current_app, render_template
  
  
  @current_app.errorhandler(404)
  def page_not_found(e):
      return render_template('404.html'), 404
  
  
  @current_app.errorhandler(Exception)
  def internal_error(e):
      return render_template('500.html'), 500
  
  
new_contents: #    Copyright 2016 Mirantis, Inc.
  #
  #    Licensed under the Apache License, Version 2.0 (the "License"); you may
  #    not use this file except in compliance with the License. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  #    License for the specific language governing permissions and limitations
  #    under the License.
  
  from flask import current_app, render_template
  
  
  @current_app.errorhandler(404)
  def page_not_found(e):
      return render_template('errors/404.html'), 404
  
  
  @current_app.errorhandler(Exception)
  def internal_error(e):
      return render_template('errors/500.html'), 500
  
  
subject: Fix error templates