https://stackoverflow.com/questions/32061598/how-to-start-or-activate-a-network-with-libvirt
conn = libvirt.open('qemu:///system')
# Define a new persistent, inactive network
xml = open('net.xml', 'r').read()
net = conn.networkDefineXML(xml)
# Set it to auto-start
net.setAutostart(True)
# Start it!
net.create()