:return: all knows NIC

def get_nics():
        """
        :return: all knows NIC
        """
        LOGGER.debug("NICService.get_nics")
        args = {'http_operation': 'GET', 'operation_path': ''}
        response = NICService.requester.call(args)
        ret = None
        if response.rc == 0:
            ret = []
            for nic in response.response_content['nics']:
                ret.append(NIC.json_2_nic(nic))
        elif response.rc != 404:
            err_msg = 'NICService.get_nics - Problem while getting NIC. ' \
                      'Reason: ' + str(response.response_content) + '-' + str(response.error_message) + \
                      " (" + str(response.rc) + ")"
            LOGGER.warning(err_msg)
        return ret