def get_transports():
        """
        get all known transports from Ariane Server
        :return:
        """
        LOGGER.debug("TransportService.get_transports")
        params = SessionService.complete_transactional_req(None)
        if params is None:
            if MappingService.driver_type != DriverFactory.DRIVER_REST:
                params = {'OPERATION': 'getTransports'}
                args = {'properties': params}
            else:
                args = {'http_operation': 'GET', 'operation_path': ''}
        else:
            if MappingService.driver_type != DriverFactory.DRIVER_REST:
                params['OPERATION'] = 'getTransports'
                args = {'properties': params}
            else:
                args = {'http_operation': 'GET', 'operation_path': '', 'parameters': params}

        response = TransportService.requester.call(args)

        if MappingService.driver_type != DriverFactory.DRIVER_REST:
            response = response.get()

        ret = None
        if response.rc == 0:
            ret = []
            for transport in response.response_content['transports']:
                ret.append(Transport.json_2_transport(transport))
        elif response.rc != 404:
            err_msg = 'TransportService.get_transports - Problem while getting transports. ' \
                      'Reason: ' + str(response.response_content) + ' - ' + str(response.error_message) + \
                      " (" + str(response.rc) + ")"
            LOGGER.warning(err_msg)
            if response.rc == 500 and ArianeMappingOverloadError.ERROR_MSG in response.error_message:
                raise ArianeMappingOverloadError("Transport.get_transports",
                                                 ArianeMappingOverloadError.ERROR_MSG)
            # traceback.print_stack()
        return ret
get all known transports from Ariane Server
        :return: