code: def print_sorted_device_list(self, device_list=None, sort_key='sn'):
          dev_list = device_list if device_list is not None else self.get_all_devices_in_portal()
          sorted_dev_list = []
          if sort_key == 'sn':
              sort_keys = [ k[sort_key] for k in dev_list if k[sort_key] is not None ]
              sort_keys = sorted(sort_keys)
              for key in sort_keys:
                  sorted_dev_list.extend([ d for d in dev_list if d['sn'] == key ])
          elif sort_key == 'name':
              sort_keys = [ k['info']['description'][sort_key]\
                      for k in dev_list if k['info']['description'][sort_key] is not None ]
              sort_keys = sorted(sort_keys)
              for key in sort_keys:
                  sorted_dev_list.extend( [ d for d in dev_list\
                                              if d['info']['description'][sort_key] == key
                                          ]
                  )
          elif sort_key == 'portals_aliases':
              sort_keys = [ k[sort_key] for k in dev_list if k[sort_key] is not None ]
              sort_keys = sorted(sort_keys)
              for key in sort_keys:
                  sorted_dev_list.extend([ d for d in dev_list if d[sort_key] == key ])
          else:
              print("Sort key {!r} not recognized.".format(sort_key))
              sort_keys = None
          self.print_device_list(device_list=sorted_dev_list)