cityObject = etree.SubElement(cityModel, 'cityObjectMember')
bldg = etree.SubElement(cityObject, '{%s}Building' % ns_bldg)
function = etree.SubElement(bldg, '{%s}function' % ns_bldg)
function.text = '1000'
print(etree.tostring(cityModel, pretty_print=True))
lxml use namespace instead of ns0, ns1,