response = ElementRoot(CAS + 'serviceResponse')
auth_success = etree.SubElement(response, CAS + 'authenticationSuccess')
username = etree.SubElement(auth_success, CAS + 'user')
response = ElementRoot(CAS + 'serviceResponse')
auth_success = etree.SubElement(response, CAS + 'authenticationSuccess')
username = etree.SubElement(auth_success, CAS + 'user')