<?php
  
  namespace Sabre\DAVACL\PrincipalBackend;
  
  /**
   * Abstract Principal Backend
   *
   * Currently this class has no function. It's here for consistency and so we
   * have a non-bc-breaking way to add a default generic implementation to
   * functions we may add in the future.
   *
   * @copyright Copyright (C) 2007-2014 fruux GmbH (https://fruux.com/).
   * @author Evert Pot (http://evertpot.com/)
   * @license http://sabre.io/license/ Modified BSD License
   */
  abstract class AbstractBackend implements BackendInterface {
  
  }