I hope this will give you a head start:
>>> s = b"""\
... <?xml version="1.0" encoding="utf-8"?>
... <users>
... <user id="1">
... <username>xxx</username>
... <password>xxx</password>
... <email>xxx@example.com</email>
... <nickname>xxx</nickname>
... <phone>xxx</phone>
... <status>xxx</status>
... </user>
... </users>
... """
>>> t = etree.XML(s)
>>> t.xpath('//username/text()')
['xxx']
>>> t.find('user[@id="1"]/username').text
'xxx'
>>> t.find('user[@id="1"]/password').text
'xxx'
…