docs: def get_routing_areas():
          """
          :return: all routing areas
          """
          LOGGER.debug("RoutingAreaService.get_routing_areas")
          args = {'http_operation': 'GET', 'operation_path': ''}
          response = RoutingAreaService.requester.call(args)
          ret = None
          if response.rc == 0:
              ret = []
              for routing_area in response.response_content['routingAreas']:
                  ret.append(RoutingArea.json_2_routing_area(routing_area))
          elif response.rc != 404:
              err_msg = 'RoutingAreaService.get_routing_areas - Problem while getting routing areas. ' \
                        'Reason: ' + str(response.response_content) + '-' + str(response.error_message) + \
                        " (" + str(response.rc) + ")"
              LOGGER.warning(err_msg)
          return ret