docs: def managed(name, servers=None):
      '''
      Manage NTP servers
  
      servers
          A list of NTP servers
      '''
      ret = {'name': name,
             'changes': {},
             'result': True,
             'comment': 'NTP servers already configured as specified'}
  
      if not _check_servers(servers):
          ret['result'] = False
          ret['comment'] = 'NTP servers must be a list of strings'
  
      before_servers = _get_servers()
      desired_servers = set(servers)
  
      if before_servers == desired_servers:
          return ret
  
      if __opts__['test']:
          ret['result'] = None
          ret['comment'] = ('NTP servers will be updated to: {0}'
                            .format(', '.join(sorted(desired_servers))))
          return ret
  
      __salt__['ntp.set_servers'](*desired_servers)
      after_servers = _get_servers()
  
      if after_servers == desired_servers:
          ret['comment'] = 'NTP servers updated'
          ret['changes'] = {'old': sorted(before_servers),
                            'new': sorted(after_servers)}
      else:
          ret['result'] = False
          ret['comment'] = 'Failed to update NTP servers'
          if before_servers != after_servers:
              ret['changes'] = {'old': sorted(before_servers),
                                'new': sorted(after_servers)}
  
      return ret