:return: all routing areas

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