[libvirt-users] serial console

hi, when creating a domain using libvirt python api, how would i tell libvirt to use a unique serial port number for domains? in the libvirt.virConnect.defineXML(conn,domainxml) call when i create the domainxml object, i need to ensure that the part below has a unique # for target port <serial type='pty'>   <target port='0'/> </serial> <console type='pty'>   <target type='serial' port='0'/> </console> currently the domains running on hypervisors have target port numbers such as 1,2,3 and so on. thanks