def add_ostype(self, ostype, sync=True):
        """
        add a OS type to this company.
        :param ostype: the OS type to add on this company
        :param sync: If sync=True(default) synchronize with Ariane server. If sync=False,
        add the OS type object on list to be added on next save().
        :return:
        """
        LOGGER.debug("Company.add_ostype")
        if not sync:
            self.ost_2_add.append(ostype)
        else:
            if ostype.id is None:
                ostype.save()
            if self.id is not None and ostype.id is not None:
                params = {
                    'id': self.id,
                    'ostypeID': ostype.id
                }
                args = {'http_operation': 'GET', 'operation_path': 'update/ostypes/add', 'parameters': params}
                response = CompanyService.requester.call(args)
                if response.rc != 0:
                    LOGGER.warning(
                        'Company.add_ostype - Problem while updating company ' + self.name +
                        '. Reason: ' + str(response.response_content) + '-' + str(response.error_message) +
                        " (" + str(response.rc) + ")"
                    )
                else:
                    self.ost_ids.append(ostype.id)
                    ostype.sync()
            else:
                LOGGER.warning(
                    'Company.add_ostype - Problem while updating company ' + self.name + '. Reason: ostype ' +
                    ostype.name + ' id is None or self.id is None'
                )